داروهای گیاهی از دانه، تخم، ریشه، برگ ، پوست و یا گل گیاهان برای اهداف پزشکی تهیه می شود و این داروها در علم پزشکی سابقه بسیار طولانی تری در مقایسه با داروهای معمولی دارند.
نتایج مثبت به دست آمده از مصرف داروهای گیاهی این نکته را برای ما روشن می کند که این محصولات همسو با پیشرفت ها در تحقیقات کلینیکی جای خود را پیدا کرده و ارزش آنها در درمان و پیشگیری از بیماریها بیش از پیش نشان داده شده است.
What is herbal medicine?
Herbal medicine — also called botanical medicine or phytomedicine — refers to using a plant’s seeds, berries, roots, leaves, bark, or flowers for medicinal purposes. Herbalism has a long tradition of use outside of conventional medicine. It is becoming more mainstream as improvements in analysis and quality control along with advances in clinical research show the value of herbal medicine in the treating and preventing disease.
What is the history of herbal medicine?
Plants had been used for medicinal purposes long before recorded history. Ancient Chinese and Egyptian papyrus writings describe medicinal uses for plants as early as 3,000 BC. Indigenous cultures (such as African and Native American) used herbs in their healing rituals, while others developed traditional medical systems (such as Ayurveda and Traditional Chinese Medicine) in which herbal therapies were used. Researchers found that people in different parts of the world tended to use the same or similar plants for the same purposes.
In the early 19th century, when chemical analysis first became available, scientists began to extract and modify the active ingredients from plants. Later, chemists began making their own version of plant compounds and, over time, the use of herbal medicines declined in favor of drugs. Almost one fourth of pharmaceutical drugs are derived from botanicals.
Recently, the World Health Organization estimated that 80% of people worldwide rely on herbal medicines for some part of their primary health care. In Germany, about 600 – 700 plant based medicines are available and are prescribed by some 70% of German physicians. In the past 20 years in the United States, public dissatisfaction with the cost of prescription medications, combined with an interest in returning to natural or organic remedies, has led to an increase in herbal medicine use.
How do herbs work?
In many cases, scientists aren’t sure what specific ingredient in a particular herb works to treat a condition or illness. Whole herbs contain many ingredients, and they may work together to produce a beneficial effect. Many factors determine how effective an herb will be. For example, the type of environment (climate, bugs, soil quality) in which a plant grew will affect it, as will how and when it was harvested and processed.
How are herbs used?
The use of herbal supplements has increased dramatically over the past 30 years. Herbal supplements are classified as dietary supplements by the U.S. Dietary Supplement Health and Education Act (DSHEA) of 1994. That means herbal supplements — unlike prescription drugs — can be sold without being tested to prove they are safe and effective. However, herbal supplements must be made according to good manufacturing practices.
The most commonly used herbal supplements in the U.S. include echinacea (Echinacea purpurea and related species), St. John’s wort (Hypericum perforatum), ginkgo (Ginkgo biloba), garlic (Allium sativum), saw palmetto (Serenoa repens), ginseng (Panax ginseng, or Asian ginseng; and Panax quinquefolius, or American ginseng), goldenseal (Hydrastis canadensis), valerian (Valeriana officinalis), chamomile (Matricaria recutita), feverfew (Tanacetum parthenium), ginger (Zingiber officinale), evening primrose (Oenothera biennis), and milk thistle (Silybum marianum).
Often, herbs may be used together because the combination is more effective and may have fewer side effects. Health care providers must take many factors into account when recommending herbs, including the species and variety of the plant, the plant’s habitat, how it was stored and processed, and whether or not there are contaminants (including heavy metals and pesticides).
What is herbal medicine good for?
Herbal medicine is used to treat many conditions, such as asthma, eczema, premenstrual syndrome, rheumatoid arthritis, migraine, menopausal symptoms, chronic fatigue, irritable bowel syndrome, and cancer, among others. Herbal supplements are best taken under the guidance of a trained health care provider. For example, one study found that 90% of arthritic patients use alternative therapies, such as herbal medicine.Be sure to consult with your doctor or pharmacist before taking any herbs. Some common herbs and their uses are discussed below.
- Ginkgo (Ginkgo biloba) has been used in traditional medicine to treat circulatory disorders and enhance memory. Although not all studies agree, ginkgo may be especially effective in treating dementia (including Alzheimer’s disease) and intermittent claudication (poor circulation in the legs). It also shows promise for enhancing memory in older adults. Laboratory studies have shown that ginkgo improves blood circulation by dilating blood vessels and reducing the stickiness of blood platelets. By the same token, this means ginkgo may also increase the effect of some blood thinning medications, including aspirin. People taking blood thinning medications should ask their doctor before using ginkgo. Caution should also be taken with people with a history of seizures and people with fertility issues; speak with your physician.
- Kava kava (Piper methysticum) is said to elevate mood, enhance well being and contentment, and produce a feeling of relaxation. Several studies have found that kava may be useful in the treatment of anxiety, insomnia, and related nervous disorders. However, there is serious concern that kava may cause liver damage. It’s not clear whether the kava itself caused liver damage in a few people, or whether it was taking kava in combination with other drugs or herbs. It’s also not clear whether kava is dangerous at previously recommended doses, or only at higher doses. Some countries have taken kava off the market. It remains available in the United States, but the Food and Drug Administration (FDA) issued a consumer advisory in March of 2002 regarding the “rare” but potential risk of liver failure associated with kava containing products.
- Saw palmetto (Serenoa repens) is used by more than 2 million men in the United States for the treatment of benign prostatic hyperplasia (BPH), a non cancerous enlargement of the prostate gland. A number of studies suggest that the herb is effective for treating symptoms, including frequent urination, having trouble starting or maintaining urination, and needing to urinate during the night. But a well-conducted study published in the February 9, 2006 edition of the New England Journal of Medicine found that saw palmetto was no better than placebo in relieving the signs and symptoms of BPH.
- St. John’s wort (Hypericum perforatum) is well known for its antidepressant effects. In general, most studies have shown that St. John’s wort may be an effective treatment for mild to moderate depression, and has fewer side effects than most other prescription antidepressants. But the herb interacts with a wide variety of medications, including birth control pills, and can potentially cause unwanted side effects, so it is important to take it only under the guidance of a health care provider.
- Valerian (Valeriana officinalis) is a popular alternative to commonly prescribed medications for sleep problems because it is considered to be both safe and gentle. Some studies bear this out, although not all have found valerian to be effective. Unlike many prescription sleeping pills, valerian may have fewer side effects, such as morning drowsiness. However, Valerian does interact with some medications, particularly psychiatric medications, so you should speak to your doctor to see if Valerian is right for you.
- Echinacea preparations (from Echinacea purpurea and other Echinacea species) may improve the body’s natural immunity. Echinacea is one of the most commonly used herbal products, but studies are mixed as to whether it can help prevent or treat colds. A review of 14 clinical studies examining the effect of echinacea on the incidence and duration of the common cold found that echinacea supplements decreased the odds of getting a cold by 58%. It also shortened the duration of a cold by 1.4 days. Echinacea can interact with certain medications and may not be right for people with certain conditions, for example people with autoimmune disorders or certain allergies. Speak with your physician.
Buying standardized herbal supplements helps ensure you will get the right dose and the effects similar to human clinical trials. Ask your doctor or pharmacist about which herbal supplements are best for your health concerns.
Is there anything I should watch out for?
Used correctly, herbs can help treat a variety of conditions, and in some cases, may have fewer side effects than some conventional medications. But because they are unregulated, herbal products are often mislabeled and may contain additives and contaminants that aren’t listed on the label. Some herbs may cause allergic reactions or interact with conventional drugs, and some are toxic if used improperly or at high doses. Taking herbs on your own increases your risk, so it is important to consult with your doctor or pharmacist before taking herbal medicines. Some examples of adverse reactions from certain popular herbs are described below.
- St. John’s wort can cause your skin to be more sensitive to the sun’s ultraviolet rays, and may cause an allergic reaction, stomach upset, fatigue, and restlessness. Clinical studies have found that St. John’s wort also interferes with the effectiveness of many drugs, including the blood thinner warfarin (Couamdin), protease inhibitors for HIV, birth control pills, certain asthma drugs, and many other medications. In addition, St. John’s wort should not be taken with prescribed antidepressant medication. The FDA has issued a public health advisory concerning many of these interactions.
- Kava kava has been linked to liver toxicity. Kava has been taken off the market in several countries because of liver toxicity.
- Valerian may cause sleepiness, and in some people it may even have the unexpected effect of overstimulating instead of sedating.
- Garlic, ginkgo, feverfew, and ginger, among other herbs, may increase the risk of bleeding.
- Evening primrose (Oenothera biennis) may increase the risk of seizures in people who have seizure disorders and bleeding in people with bleeding disorders or who take blood thinning medications, such as Coumadin (Warfarin).
Some herbal supplements, especially those imported from Asian countries, may contain high levels of heavy metals, including lead, mercury, and cadmium. It is important to purchase herbal supplements from reputable manufacturers to ensure quality. Many herbs can interact with prescription medications and cause unwanted or dangerous reactions. For example, there is a high degree of herb/drug interaction among patients who are under treatment for cancer. Be sure to consult your doctor before trying any herbal products.
Who is using herbal medicine?
Nearly one-third of Americans use herbs. Unfortunately, a study in the New England Journal of Medicine found that nearly 70% of people taking herbal medicines (most of whom were well educated and had a higher-than-average income) were reluctant tell their doctors that they used complementary and alternative medicine.
How is herbal medicine sold in stores?
The herbs available in most stores come in several different forms: teas, syrups, oils, liquid extracts, tinctures, and dry extracts (pills or capsules). Teas can be made from dried herbs left to soak for a few minutes in hot water, or by boiling herbs in water and then straining the liquid. Syrups, made from concentrated extracts and added to sweet tasting preparations, are often used for sore throats and coughs. Oils are extracted from plants and often used as rubs for massage, either by themselves or as part of an ointment or cream. Tinctures and liquid extracts are made of active herbal ingredients dissolved in a liquid (usually water, alcohol, or glycerol). Tinctures are typically a 1:5 or 1:10 concentration, meaning that one part of the herb is prepared with 5 – 10 parts (by weight) of the liquid. Liquid extracts are more concentrated than tinctures and are typically a 1:1 concentration. A dry extract form is the most concentrated form of an herbal product (typically 2:1 – 8:1) and is sold as a tablet, capsule, or lozenge.
No organization or agency regulates the manufacture or certifies the labeling of herbal preparations. This means you can’t be sure that the amount of the herb contained in the bottle, or even from dose to dose, is the same as what is stated on the label. Some herbal preparations are standardized, meaning that the preparation is guaranteed to contain a specific amount of the active ingredients of the herb. However, it is still important to ask companies making standardized herbal products about their product’s guarantee. It is important to talk to your doctor or an expert in herbal medicine about the recommended doses of any herbal products.
Are there experts in herbal medicine?
Herbalists, chiropractors, naturopathic physicians, pharmacists, medical doctors, and practitioners of Traditional Chinese Medicine all may use herbs to treat illness. Naturopathic physicians believe that the body is continually striving for balance and that natural therapies can support this process. They are trained in 4-year, postgraduate institutions that combine courses in conventional medical science (such as pathology, microbiology, pharmacology, and surgery) with clinical training in herbal medicine, homeopathy, nutrition, and lifestyle counseling.
How can I find a qualified herbalist in my area?
For additional information, or to locate an experienced herbalist in your area, contact the American Herbalists Guild (AHG) at site at www.americanherbalistguild.com. To located a licensed naturopath in your area, call the American Association of Naturopathic Physicians (AANP) at www.naturopathic.org.
What is the future of herbal medicine?
In some countries in Europe — unlike the U.S. — herbs are classified as drugs and are regulated. The German Commission E, an expert medical panel, actively researches their safety and effectiveness.
While still not widely accepted, herbal medicine is being taught more in medical schools and pharmacy schools. More health care providers are learning about the positive and potentially negative effects of using herbal medicines to help treat health conditions. Some health care providers, including doctors and pharmacists, are trained in herbal medicine. They can help people create treatment plans that use herbs, conventional medications, and lifestyle changes to promote health.
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