Herbs were the first 'drugs' and primary medicine used by man.
Medicine men and folk healers learnt the medicinal use of herbs and animal matter by observing their effects on humans. Medicine has since come a long way from such simple trial and error.
Here are some common health supplements used in Western alternative medicine and Traditional Chinese Medicine (TCM) and some significant related research findings.
Gingko biloba is a popular herbal supplement widely promoted as a memory enhancer.
In October 2008, The New York Times reported that new research suggests a daily dose of gingko biloba may help prevent brain damage after a stroke.
The findings, published online in the medical journal Stroke, have been shown only in mice but researchers said the studies supported theories that the herb may help stroke patients.
St John's wort
This plant has been traditionally used to treat anxiety, depression and mental disorders.
In October 2008, it was reported that an analysis of previous studies found that St John's wort can effectively treat symptoms of major depression.
Extracts of the herb tested in different trials were better than placebos and as effective as standard anti-depressants with fewer side effects, the researchers reported in the Cochrane Reviews, a medical and scientific studies journal.
Fish oils are a source of omega-3 fatty acids and are thought to be beneficial for the heart.
Studies on fish oil therapy have had mixed results. In September 2008, The New York Times reported that a clinical trial in Australia, published in The Journal Of Developmental And Behavioral Pediatrics, found improvements in parents' ratings of their children's hyperactivity and inattention but no difference in teachers' assessments.
Meanwhile, an Oxford-Durham study in Britain, published in the journal Pediatrics in 2005, reported remarkable improvements in reading and spelling among children treated with omega-3 fatty acids.
It is important to buy only purified pharmaceutical-grade fish oil to minimise the risk of mercury contamination.
Parts from the echinacea plant have traditionally been used to treat or prevent colds, flu and other infections.
The Los Angeles Times reported in February 2008 that an analysis published in the journal Lancet Infectious Disease showed that in well-designed studies, the Echinacea purpurea species shortened colds by an average of 1.4 days and reduced the odds of getting a cold by 58 per cent.
A Cochrane review concluded that only Echinacea purpurea products showed any promise in treating colds and only when they contained the above-ground parts of the plant - not the root.
Echinacea products can contain the roots, leaves or flowers of any of three species of the plant (purpurea, pallida or angustifolia), in dried, powdered or extracted form.
Evening primrose oil
Evening primrose oil contains gamma-linolenic acid (GLA), an essential fatty acid. It is used for many conditions including eczema and to alleviate breast pain or menstrual discomfort.
The US National Centre for Complementary and Alternative Medicine states that evening primrose oil may have modest benefits for eczema and may be useful for rheumatoid arthritis and breast pain. However, study results are mixed and most studies are small and not well-designed.
In TCM, the tian qi plant is said to improve blood circulation and to lower cholesterol. However, it is generally regarded as unsafe for pregnant women.
Dried seahorses are commonly used in TCM cures.
Mr Wu Yue, TCM physician at Raffles Chinese Medicine, said that in TCM, seahorses are considered 'warm' and are used to increase and balance energy flows within the body. They are also used to treat many conditions including impotence and infertility, heart disease, respiratory disorders and skin ailments.
Yin yang huo (horny goat weed)
This herb is said to help prevent impotence and increase one's libido.
In September, Italian researchers found that yin yang huo, known in English as horny goat weed, could be a promising alternative to Viagra for impotent men.
The researchers modified a compound in the plant called icariin and found that it blocked the erection-inhibiting enzyme that restricts blood flow around the body - including to the penis - as well as Viagra did.
Further tests on animals and humans are needed but the researchers said that the extract from the herb represents a potential new erectile dysfunction treatment with fewer side effects.
Crushed pearl powder
Crushed pearl power, deemed good for the complexion, is consumed or used as an ingredient in face creams.
Mr Carl Wong, head acupuncturist at Healthway Medical Group's TCM Wellness, said crushed pearl powder has anti-ageing properties, can smoothen and brighten the skin and is also a cure for insomnia.
Mr Wu Yue, TCM physician at Raffles Chinese Medicine, said that bird's nest - often prepared as a soupy tonic - is believed to have health-enhancing and anti-ageing properties.
However, he also said that it may be a common cause of food-induced anaphylaxis - a severe whole-body allergy - in children.
Dr Phuah Huan Kee, senior consultant at Singapore Baby and Child Clinic, said allergic reactions to bird's nest can sometimes be life-threatening.
Chinese cordyceps is the result of a parasitic relationship between a moth caterpillar and a special fungus.
Mr Wu said that cordyceps have major uses in TCM including in the prevention of cardiovascular problems, boosting the immune system, increasing libido and strengthening the lungs. However, he said there is insufficient scientific research on the safety of children, pregnant or lactating women consuming cordyceps.
This story was first published in Mind Your Body, The Straits Times, on Nov 6, 2008.