Since 1999, the National Institutes of Health has been funding herb research, a breakthrough from the long-held position that natural medicine was not effective enough to merit investigation. The National Center for Complementary and Alternative Medicine (NCCAM), in charge of such research, has already conducted over 100 clinical trials and funded training for the new expert centers opening nationwide.

Melatonin, for example, is under research by the University of California together with the National Institute of Nursing Research, as a possible treatment in sleep disorders associated with Parkinson's Disease. As most research will take years before any clear conclusion can be drawn, approach the taking of any herb with caution and always consult your health care provider.

Here is a list of herbs heavily investigated and currently under research and clinical trials around the world.

Una de Gato

Una de gato (Spanish for "cat's claw") has only gained popularity in the US in the last few years, but people from South America have been using it for almost two centuries as an immune-fortifying tonic and a treatment for arthritis.

Cat's claw only grows in the rainforests of Peru, where the government has strict harvesting policies in place. Since it takes over 20 years for the plant to mature enough to be harvested, the herb is only available on limited supplies and tends to be expensive.

Best known for its cleansing and detoxification properties, recent research has suggested it could boost the immune system enough to help it fight diseases such as HIV. In fact, several European countries are conducting clinical trials using a combination of cat's claw with several commercial drugs to treat AIDS.

High in powerful antioxidants (including proanthocyanidins) and alkaloids, it can also help against damage caused by free radicals, lower blood pressure, reduce cholesterol, and inhibit blood platelet aggregation.

Passion flower

Passion flower, a climbing vine grown in tropical gardens because of its beautiful purple-pink flowers, has been used by Native Americans for over a century.

The plant contains beta-carbolines, a MAOI with sedative properties, which also helps in the treatment of insomnia and hysteria. Preliminary research shows passion flower to be effective in treating a variety of disorders of the nervous system. A double-blind study conducted in 2003 showed passion flower to be as effective as Serax® (a prescription drug) to treat anxiety.

The herb is very popular in Europe. In Germany, over 50 sedative products contain passion flower as one of the primary ingredients.

A very effective, non-invasive anti-bacterial, passion flower has a history of being used to treat eye infections, skin irritations, and burns.

Catnip

Best known for its ability to make cats "happy," catnip actually has human applications as well. People have no physical reaction to catnip, at least not the way their feline companions do. In humans, catnip can be taken as a tea to treat colds, flues, and fevers, as well as for its sedative properties. Catnip was used during the Middle Ages to treat a number of childhood diseases, including diarrhea and colic. Alternative modern medicine agrees that it can also prevent morning sickness in pregnant women.

In 2001, Iowa State University issued the results of a finding confirming that oil extracted from catnip is about 10 times more effective at repealing mosquitoes that commercial DEET. According to other studies, catnip is also very effective against cockroaches and other household pests.

Dandelion (Taraxacum)

Named from the Old French word, dent-de-lion ("lion's tooth"), dandelion is better known today in most of Europe as pissenlit ("urinate in bed"), a direct allusion to its diuretic properties.

Dandelion is grown at a small scale as a vegetable --The raw leaves can be made into soups and salads or used to prepare dandelion wine. Dandelion's root is sometimes roasted and used as a substitute for coffee.

Dandelion is a powerful diuretic, available only by prescription in Canada and some European countries. Other medicinal applications take advantage of the plant's condition to treat anemia and jaundice. Dandelion's milk can get rid of warts in just a few applications.

Licorice

Better known as a candy, the licorice herb is one of the most cultivated herbs in the world because of its medicinal properties. Licorice extract (produced by boiling the plant's roots) is 50 times sweeter than sucrose, and is widely used as syrup in OTC expectorants. In appropriate doses, it can be as effective as codeine to treat throat irritations and dry coughs; in large doses, licorice is a laxative.

Widely used in Asia to treat hepatic conditions (hepatitis included), it is also prescribed in China as a remedy for gastric irritation and intestinal ulcers. Research is being conducted in Japan to study the possible use of licorice against the HIV virus. Externally, it can be used to treat skin infections.

Psyllium

Psyllium has a long list of medicinal applications as an antitoxic, antimicrobial, and anti-inflammatory. Since ancient times, it has been used for constipation, to treat irritable bowel syndrome and clean the colon, and as a diuretic. The seed husks of psyllium are widely used in OTC laxatives and fiber supplement products such as Metamucil.

Internally, the herb is astringent, demulcent, and expectorant, and it's used as a remedy to lower cholesterol and control diabetes. Externally, it can be applied as a poultice to treat insect bites, poison ivy rashes, and minor burns.

Marine Algae

Algae may be the oldest natural supplement available, as fossil records indicate they were already around during the Precambrian period, approximately 3 billion years ago.

Algae's major claim to fame is its ability to increase white blood cell count and fight anemia, fatigue, and infections. An excellent source of vitamins, carotenoids, amino acids, and enzymes, algae offer a significant supply of protein for vegetarians. There are four types of algae that are especially nutritious: Spirulina (used as a treatment for obesity), chlorella (high in chlorophyll and antioxidants), Klamath Lake blue-green (high in vitamin B12), and red marine algae (rich in fiber and complex carbohydrates).

All types of algae are used to treat anemia and as an overall health enhancer.

Bilberry

Bilberry was widely used by British pilots during WWII to improve night vision before night bombing raids. It is also said to halt or prevent effects of macular degeneration, glaucoma, and myopia, supposedly because of its effect on the tiny capillaries that make up the eye.

Bilberry is now being studied as a possible treatment for varicose veins and thrombosis.

Feverfew

Modern research has shown feverfew to be an effective remedy for migraines and headaches, although it seems the herb is more effective at preventing rather than treating migraines. It also appears to work better on people who have not responded to conventional therapies.

Folk medicine also uses feverfew as a treatment for fevers and painful ailments, including arthritis and muscle tension.

Feverfew is a very adaptable herb and can be equally effective fresh or dried, as capsules, or in liquid-extract forms.

Golden Seal

Golden Seal was highly valuable to Native Americans, who used extensively for its antiseptic properties. The herb acts as an antibiotic, anti-inflammatory, and haemostatic. It's especially effective in treating bladder infections, and as a tonic and diuretic.

Often marketed as a multi-purpose remedy, it has gained such popularity in the last ten years that prices have soared, making it one of the most expensive herbs available, especially in salve form (tablets are somewhat less expensive, but also less concentrated). Widely used in western medicine in the treatment of respiratory and digestive diseases, golden seal is a common ingredient in herbal supplements, from allergy remedies to decongestant nose sprays. It is also promoted as a "blood cleanser" to prepare for drug and alcohol tests.

Golden seal is now being studied as a possible treatment for cancers of the ovaries and uterus.

While the plant itself is poisonous, the commercial-strength extract has few contraindications, especially in small doses (long-term used is not recommended). Golden seal can induce early labor, so it should be avoided by pregnant women.