The Everything Guide to Herbal Remedies: An easy-to-use reference for natural health care


Strengthening Immunity

Herbs have been used for centuries to support immune function and, when needed, to kick it into overdrive to beat an infection or disease. And while conventional medicine has traditionally focused its immune-system strategies on curing infections, herbalism has centered on the belief that supporting and nourishing the immune system will result in fewer and less severe infections—and better health overall. Happily, conventional practitioners are increasingly supportive of this notion, and research consistently proves the immune-boosting power of herbs.

Immunity and the Immune Response

It all starts here, with your immune response: the way your body recognizes and defends itself against bacteria, viruses, and any other foreign and potentially harmful substances. You won’t stay healthy—or alive—for long if your immune system isn’t working properly.

Your immune system is a layered series of defenses, starting with simple physical barriers (like your skin and mucous membranes) and finishing with a sophisticated system of chemical messengers and cellular warriors, designed to fend off attack from all kinds of disease-causing agents.

The immune system works by recognizing antigens and producing specific antibodies to destroy them. An antigen is any substance that is perceived by your body as a threat—and therefore causes your immune system to produce antibodies against it. Antigens can be foreign substances, such as bacteria, viruses, or chemicals, but they also can be formed within your body (examples might be cancer cells or the toxins created by invading bacteria).

The nemesis of any antigen is its antibody. Antibodies are a type of protein custom-made by the immune system to fight specific antigens. Each is unique and defends the body against only one type of antigen.

Many chronic conditions, including diabetes, cancer, and liver disease, can reduce your body’s resistance to germs, slow the healing of wounds, and set the stage for infection. So can poor nutrition, certain medications (like steroids), and anything that inhibits circulation and the flow of oxygen in your body, such as hypertension, heart disease, and smoking.

White blood cells, or leukocytes, seek out and destroy invading substances. One type of leukocytes are lymphocytes, which come in two varieties: B cells and T cells. B cells produce antibodies, and T cells attack antigens directly (they also help control the immune response).

Other chemicals include eicosanoids and cytokines, which are released by injured or infected cells and attract leukocytes and other immune cells to the scene to kill off the pathogens.

Your immune system also includes several structures—the lymph nodes, thymus, spleen, and marrow in the long bones in your arms and legs—that produce and store leukocytes.

Everyone has a few kinds of immunity, including:

• Innate (or nonspecific) immunity is your first line of defense, a set of built-in barriers that keep harmful substances out of your system. Examples include your skin, your cough reflex, and germ-fighting fluids like mucus, tears, and stomach acid.

• Acquired (or adaptive) immunity, also known as specific immunity, is created as you’re exposed to various antigens and your body develops defenses to protect you against them. Your system “learns” to recognize and attack antigens and develops immunity to certain infections.

Immune Function and Disease

Over the course of your lifetime, your immune system will face a multitude of challenges—from external pathogens as well as your body’s own tissues and processes. An infection occurs when bacteria or other microbes get into your body and begin to multiply. The situation officially turns into a disease when the infection does damage to the cells and tissues and creates symptoms of illness. Illness can also occur when your immune system is pushed off course by problems known as immune deficiency disorders, or immunodeficiencies.

When it comes to human health, infectious agents can be broken into four categories: parasites, bacteria, viruses, and fungi.

• Infectious parasites include the protozoa, or single-celled organisms, that cause malaria and a few types of foodborne illness. (Other protozoa, such as plankton, are harmless.)

• Bacteria are tiny, single-celled creatures that can live on nonliving surfaces (such as countertops and stair railings) as well as on (or in) a living host.

• Viruses are tiny microbes that contain one or two molecules of genetic material. They can’t live on their own but instead must “hijack” living cells in order to survive and multiply.

• Fungi are actually primitive plants (they include mushrooms, molds, and yeasts).

In healthy people, the immune system is ready and able to meet most of the challenges it will face. You’ll encounter pathogens and, if they’re strong or plentiful enough, you’ll develop an infection, which your body will eventually defeat, and you’ll go on to fight another day.

However, in people with compromised immunity, even the smallest threat—or things that aren’t threatening at all, such as allergens or the body’s own cells—can create serious, potentially fatal problems.

Many herbs and supplements are known as “immune-stimulating” agents, but not every immune system needs stimulating: If you’ve got allergies, asthma, or an autoimmune disorder, you’ve got an overactive immune system. Thus, you need something that’s “immune-modulating” to help regulate your body’s immune response (and turn it down, if necessary).

Herbs: Your Immune System’s Best Friend

Herbal medicine has a centuries-old tradition of nurturing immune function—of keeping people healthy by treating them before they get sick—with an array of immunity-modulating and immunity-boosting plants.

One of the guiding principles of herbal medicine is the support of immune functioning through herbs known as adaptogens or tonics (see Chapter 2). Adaptogenic herbs help your body deal with the ill effects of stress—which can be caused by many things, including trauma, injury, or infection—without getting sick. Tonics are typically used to shore up a system that needs “toning” or “tonifying” (meaning it’s failing or just performing below par).

Several herbs have demonstrated a direct effect on the immune system. Some, like barberry (Berberis vulgaris), echinacea (Echinacea purpurea), and goldenseal (Hydrastis canadensis), contain high concentrations of chemicals that increase immune system activity and thus are considered immunostimulants.

Exercise is a proven immunity booster. It flushes bacteria and other pathogens from the respiratory and urinary tracts (and skin, via sweat), increases circulation of antibodies and white blood cells, and slows the release of the stress-related hormones that can contribute to disease. Exercise even raises your body temperature, which acts like a fever to kill off infectious microbes.

Other herbs contain constituents that modulate the immune response, increasing immune activity when it’s called for (i.e., when an infection is looming) and turning it down when necessary (in the case of allergies or autoimmune disorders). These are called immunomodulators, and they include astragalus (Astragalus membranaceus), Asian ginseng (Panax ginseng), licorice (Glycyrrhiza glabra), and reishi (Ganoderma lucidum); many of the herbs known as adaptogens are considered immunomodulators.

Sneezes, Sniffles, and Sore Throats

Upper respiratory infections are among the most common illnesses in the United States. They’re highly contagious and are spread by both airborne particles and particles passed through physical contact (touching an infected person or an object he’s touched). Colds or flu can precipitate other problems, such as bronchitis or sinusitis (inflammation in the bronchial passages or sinuses).

Colds are caused by viruses—experts have identified at least 200 different kinds—most of which cause sneezing, scratchy throat, and runny nose.

Influenza, or the flu, is a more severe upper respiratory infection caused by the influenza virus (there are three types, commonly known as A, B, and C, of which A and B are the most serious). Flu symptoms are more intense than those of a cold and typically include fever and muscle aches.

Strep throat is caused, as you might have guessed, by Streptococcus (strep) bacteria. It’s characterized by sudden and acute throat pain and sometimes fever, headache, nausea, and vomiting. In most cases, your throat will be bright red and the lymph nodes in your neck will be swollen and tender.

Hand washing is the best way to avoid catching many kinds of infections (cold and flu viruses can live up to three hours on your skin and just as long on hard surfaces like telephones and stair railings). Try using soap or liquid cleanser made with rosemary (Rosmarinus officinalis): It has proven antiviral and antibacterial powers.

Treatment Options

Strep infections are always treated with antibiotics like penicillin. To relieve throat pain, most conventional doctors recommend over-the-counter (OTC) sprays or lozenges made with topical anesthetics like benzocaine, which can cause irritation or allergic reactions in some people.

To prevent the flu, experts recommend an annual flu shot (or Flumist, a nasal spray). Some doctors also prescribe antiviral drugs like zanamivir (Relenza) and oseltamivir (Tamiflu), which can prevent an infection or lessen its severity and duration if taken within forty-eight hours of onset. These drugs can produce side effects like abdominal pain, diarrhea, and nausea.

Most people treat colds and flu with OTC pain relievers, decongestants, antihistamines, and cough medicines. These drugs can cause a long list of side effects, including irregular heartbeat, drowsiness, and stomach pain (see Chapter 13). Here are some herbal options:

• Andrographis (Andrographis paniculata)

Andrographis is used in Ayurvedic and Chinese medicine to treat upper respiratory tract infections (it’s an antibacterial and antioxidant). Studies show that it can relieve the symptoms of sore throats and helps to prevent colds.

• Astragalus (Astragalus membranaceus)

Astragalus is used in Traditional Chinese Medicine as a tonic for the immune system. Studies show that it’s an antiviral, antibacterial, and immunomodulator that helps prevent infections.

• Echinacea (Echinacea purpurea)

Echinacea is a powerful antiviral and immune system stimulant, and has been shown in several studies to reduce the severity and duration of cold and flu symptoms.

• Elderberry (Sambucus nigra)

Elderberry has both antiviral and immune-boosting effects, making it a great remedy for colds and flu. Research shows it can fight several viruses at once—and improve your symptoms in just a few days.

• Ginger (Zingiber officinale)

Ginger inhibits the bacteria and viruses responsible for upper respiratory infections and also relieves sore throats and the aches of the flu.

• Isatis (Isatis tinctoria)

Constituents of this Chinese herb have antiviral, antibacterial, antifungal, analgesic, and antipyretic (fever reducing) activity.

Common Viral Infections

The most common viral infections in humans, by far, are colds and flu. But viruses can also cause infections and diseases ranging from mild (mononucleosis) to severe (dengue fever and AIDS).


Warts are small, generally harmless growths on the skin. Most often they’re just ugly, but in some cases they can be problematic. Common warts appear most often on the hands; plantar warts are on the soles of the feet; genital warts are found in the pubic area and on the genitals. They’re caused by human papillomavirus, or HPV, a version of which can lead to cervical cancer.

OTC wart medications containing concentrated salicylic acid (Compound W, Transversal PlantarPatch) are often recommended for warts (except those on the face or genitals). These products dissolve the wart over a period of weeks, but they’re highly corrosive and can burn the surrounding skin if not applied carefully. Some doctors prescribe stronger medications or remove warts via surgery, cyrotherapy (freezing), or electrocautery (burning). Genital warts are often treated with topical applications of imiquimod (Aldara), an immunomodulating drug that can cause itching, burning, and other side effects.

Cold Sores

Cold sores, also known as oral herpes or fever blisters, are caused by a type of herpes simplex virus (a relative of the one that causes genital herpes; see below). This infection is highly contagious—and permanent (it can recur indefinitely). After the initial sore heals, the virus settles into a dormant state in your nerve cells, where it will remain until it’s reactivated (often by stress, trauma, or excessive sun exposure).

Many plants are natural antivirals. Green tea extracts can fight flu viruses and are also the key ingredient in sinecatechines (Veregen) ointment, a prescription drug that’s approved by the FDA as a treatment for genital warts. Another genital wart drug, podophyllotoxin (Podofilox), is derived from two types of mayapple trees, Podophyllum peltatum and P. hexandrum.

Treatment Options

Conventional medicine treats viral infections with oral or topical prescription medications such as acyclovir (Zovirax) or penciclovir (Denavir), which suppress the virus. Acyclovir can cause side effects like diarrhea and vomiting (in the oral preparation) and burning and inflammation (in the topical form). Topical denavir can cause headache, skin reactions, and changes in your sense of smell or taste. These herbs offer another type of relief:

• Echinacea (Echinacea purpurea)

Echinacea is a powerful weapon against viral infections. It’s lethal to several pathogenic viruses, including the strain of herpes that causes cold sores, and can help boost your internal defenses as well.

• Garlic (Allium sativum)

Garlic is a proven antiviral and can help fight infection both inside and out. Research shows that fresh garlic extracts can eradicate the viruses that cause herpes (as well as influenza and the common cold), and an isolated garlic compound has been shown effective against warts.

• Isatis (Isatis tinctoria)

This Chinese herb, taken in combination with astragalus (Astragalus membranaceus), accelerates the healing of cold sores and warts.

• Lemon balm (Melissa officinalis)

Topical applications can reduce the size and severity of cold sores, shorten their healing time, and prevent the spread of the infection.

• Licorice (Glycyrrhiza glabra)

Licorice root contains phytochemicals that have been proven effective against several types of infectious viruses, including those that cause cold sores.

• Sage (Salvia officinalis, S. lavandulaefolia)

Applied topically, sage extracts can halt viral infections. Research shows that a combination of sage and rhubarb (Rheum officinale, R. palmatum) can heal cold sores as well as the prescription drug acyclovir.

Bacterial Infections

Bacteria are everywhere, and most of the time they’re harmless (some are even beneficial to human health, such as the Lactobacillus, a.k.a. “friendly” bacteria, in yogurt). But whenever there’s a break in the structural integrity of your skin—whether it’s a burn, a superficial scrape, or a deep puncture—you’re opening the door to bacteria. If enough of them get in to overpower your body’s defenses, you’ll have an infection.


Although any wound is open to bacterial invasion, open wounds (ulcers), large or severe burns, and bites are the most likely to become infected. Signs of infection include acute pain (it hurts more than you think it should), pus, and swelling that extends past the immediate area and feels hot.

Many bacterial infections in humans can be traced to two kinds of bugs: Staphylococcus (staph) and Streptococcus (strep) bacteria. Staph infections typically involve the skin but can also affect the internal organs. Strep bacteria cause strep throat as well as several skin infections. Both are producing increasing numbers of drug-resistant strains.

Conventional treatment will depend on the severity of the infection. In many cases, you’ll be given a prescription for oral antibiotics that are effective against the bacteria causing your infection. Oral antibiotics can contribute to the development of drug-resistant bacteria, and taking them long term can compromise your immunity.


This inflammation of the hair follicles can occur anywhere there’s hair. In most cases, the problem starts when the follicles are damaged by friction or abrasion (as in shaving), or blockage (wearing tight clothing), then invaded by Staphylococcus bacteria.

Conventional medicine typically treats folliculitis with antibacterial cleansers like triclosan (Dial Antibacterial Moisturizing Body Wash) or triclocarban (Safeguard Antibacterial Soap). These are serious chemicals—they’re also used in industrial disinfectants—that have been linked to neurological and hormonal problems. You also may be given a prescription for an oral antibiotic (see above) or a topical antibiotic like mupirocin (Bactroban), which can cause burning, pain, and itching.

Other Skin Infections

Impetigo is a superficial skin infection caused by staph or strep bacteria. It produces small blisters or scabs that generally start on the face and may move to other parts of the body.

Cellulitis is an infection of the deep layers of the skin caused by bacteria—most often strep—that enter through a cut, burn, or other skin injury. Left untreated, it can spread to the lymph nodes and become life threatening. People who already have another type of infection or a chronic condition (like diabetes) that can impair circulation are most at risk of developing cellulitis.

Conventional Versus Herbal Solutions

Conventional medicine treats impetigo with prescription-strength topical antibiotics (see above); more serious cases might get a prescription for oral antibiotics. Cellulitis is treated with oral antibiotics (see above).

Many herbal remedies can be used alone or in conjunction with antibiotics to treat bacterial infections:

• Barberry (Berberis vulgaris)

Barberry contains powerful antibacterial and anti-inflammatory chemicals that can inhibit bacteria from attaching to human cells. The same antibacterial chemicals are found in goldenseal (Hydrastis canadensis).

• Cat’s claw (Uncaria guianensis, U. tomentosa)

This traditional Peruvian remedy has proven antimicrobial effects—and can inhibit the activity of strep, staph, and other bacteria. It’s also a proven anti-inflammatory and immunomodulator.

• Gotu kola (Centella asiatica)

This herb is used in Ayurvedic medicine to foster all kinds of tissue repair. Recent research shows its ability to kick-start immune response, speed skin healing, and inhibit bacterial growth.

• Saint John’s wort (Hypericum perforatum)

Best known for its antidepressant capabilities, Saint John’s wort is also a traditional remedy for skin problems caused by bacterial infection.

• Witch hazel (Hamamelis virginiana)

Witch hazel bark is a classic treatment for itchy and inflamed skin (it’s also astringent, so it helps dry up blisters). Recent research shows it can help halt staph infections (even the drug-resistant kind).

Fungal Infections

The world is full of molds, yeasts, and other types of fungi, most of which do more good than harm (think beer and penicillin). And most of the time, even pathogenic fungi can live in and on the body without any problem. But these organisms can cause infection if their numbers get out of control or if the body’s immune system is suppressed.

Ringworm has nothing to do with worms (even though its scientific name, tinea, means “growing worm” in Latin.) It got its moniker because a tinea capitis infection sometimes has a round shape, as if a worm were curled up under the skin. Ringworm is an infection of a type of fungi called der-matophytes, which may—or may not—line up in a ring-like formation.

Tinea Infections

Parasitic fungi called dermatophytes are responsible for the superficial skin infections commonly, if crudely, known as ringworm (tinea capitis), athlete’s foot (tinea pedis), and jock itch (tinea cruris). A tinea infection usually isn’t serious, but it can be itchy and uncomfortable; when it strikes the scalp, it can cause hair loss. Tinea-causing fungi thrive in warm, damp places, and are spread by direct contact: You can catch them by touching a person (or a pet) who’s infected or from a damp surface, such as the shower in the health club.

Tinea infections can also occur around and under the nails—most often, the toenails—leaving them yellowed, thickened, and crumbling. This condition is called tinea unguium.

Candida Infections

Candida infections, called candidiasis, are caused by the yeast-like fungus Candida albicans. Vaginal candidiasis is characterized by sticky white or yellowish discharge, burning, and itching (see Chapter 3). Other Candidainfections include oral thrush, which affects the mouth and throat, and skin infections like intertrigo (which occurs in skin folds) and some cases of diaper rash (see Chapter 6).

Conventional Treatments

Most tinea infections are treated with OTC topical antifungals such as clotrimazole (Mycelex, Lotrimin), or miconazole (Desenex, Monistat), which occasionally cause skin reactions. Scalp ringworm and toenail fungus are almost always treated with oral medications like itraconazole (Sporanox) or terbinafine (Lamisil), which can cause intestinal problems, rashes, and headaches. In cases of scalp ringworm, OTC dandruff shampoos that contain selenium sulfide (Selsun Blue) are sometimes recommended to prevent the spread of the fungi, but they can’t eliminate it.

Newborns can actually be more resistant to infection than you’d think. Every baby is born with a set of built-in antibodies that were passed along from his mother, which creates what’s known as passive immunity. By his first birthday, however, the child will have lost this protection—and his body will already have started making antibodies of its own.

Candidiasis is treated conventionally with OTC antifungal remedies such as miconazole (Monistat) and butoconazole (Mycelex), which can cause skin reactions and intestinal discomfort. Some doctors may also prescribe oral antifungals, such as fluconazole (Diflucan) or ketoconazole (Nizoral). Fluconazale can cause diarrhea and headaches; ketoconazole can cause nausea and abdominal pain.

Herbal Alternatives

Herbal remedies can be used in conjunction with these medicines, and include the following:

• Camphor (Cinnamomum camphora)

This natural fungicide can clear up a case of tinea unguium (research shows it’s active against the most common fungal culprits).

• Echinacea (Echinacea purpurea)

This immune-boosting herb can help pharmaceuticals fight fungal infections even better than they could alone. Research shows that combining an oral echinacea preparation with a conventional antifungal cream can significantly reduce the rate of recurrent infections.

• Garlic (Allium sativum)

Fresh garlic extracts are lethal to tinea-causing fungi, and research using ajoene, an isolated garlic constituent, found that it cleared up athlete’s foot, ringworm, and jock itch infections as well as the prescriptiondrug terbinafine.

• Lavender (Lavandula angustifolia)

A natural anesthetic and anti-inflammatory, lavender oil is also an effective weapon against the Candida albicans fungus.

• Pomegranate (Punica granatum)

Pomegranate has proven fungicidal and wound-healing properties. Topically applied extracts of pomegranate peel, combined with gotu kola (Centella asiatica), have been shown to clear up oral candidiasis as well as pharmaceutical antifungals.

• Tea tree (Melaleuca alternifolia)

A traditional Aboriginal treatment for all types of skin inflammation, tea tree oil can also kill Candida albicans and other fungi.

Immunodeficiency Disorders

Immunodeficiency disorders—a class of conditions that includes primary (inherited) and secondary (acquired) disorders—can create a seemingly endless stream of infections that often lead to serious complications. For example, people with acquired immunodeficiency syndrome (AIDS) are prone to opportunistic infections, which are potentially life-threatening conditions that might not cause any problem in a healthy person. AIDS also makes infections harder to treat and creates more serious complications from run-of-the-mill infections like a cold or the flu.

Conventional medicine typically treats immunodeficiency disorders with drugs designed to prevent specific infections: antivirals like amantadine (Symmetrel) or acyclovir (Zovirax) or vaccines that protect against infections like the flu.

Immunodeficiency disorders can come from a prolonged illness (like cancer or diabetes) or infection (AIDS is caused by the HIV virus). Malnutrition can also trigger them—a shortfall of nutrients that puts you at less than 80 percent of your recommended weight can cause severe immune system impairment—as can immunity-suppressing treatments like chemotherapy and radiation.

Several herbs can also help support immune function to treat or prevent secondary infections (although experts warn people with immunity deficiencies to avoid immunostimulating herbs). Herbs can also treat the various symptoms of infection and relieve the side effects of conventional drug therapies. They include:

• Amla (Emblica officinalis, Phyllanthus emblica)

Also known as amalaki, this Ayurvedic herb is an adaptogen, antioxidant, and antiviral; it’s also a key ingredient in the Ayurvedic remedy known as triphala. Studies show it can speed the healing of infected wounds, inhibit the activity of HIV, and kill several types of infectious bacteria in HIV-infected patients.

• Licorice (Glycyrrhiza glabra)

A staple in the pharmacies and pantries of China, Europe, and the Middle East, licorice has proven immunomodulating effects, which can help avert secondary infections.

• Lemon balm (Melissa officinalis)

Lemon balm is a traditional remedy for viral infections, and extracts have shown specific activity against HIV. Peppermint (Mentha x piperita) and sage (Salvia officinalis, S. lavandulaefolia)have similar anti-HIV action.

• Tea tree (Melaleuca alternifolia)

This herb is a potent antimicrobial, and research shows it can kill the Candida fungi that cause infections in immune-compromised people.