In despair, Sarah finally turned to an alternative treatment recommended by a friend - regular doses of Hemp Seed Oil. Within weeks, the itchy sores had vanished. "I noticed the change almost straight away. Her skin became peachy," says Sarah, who lives in Oxfordshire with her husband, Mark, and their three children. Two years later, Isobel is fine, although she still needs to take a spoonful of the oil every day. "If she misses a day, the eczema flares up again," says Sarah.

Joanna Peters has suffered from severe PMT since her early twenties. Unwilling to take hormone pills, she started on a regime of Hemp Seed oil last year. "It took about three weeks to make a difference, but it really has worked for me," says Joanna, 41, who works in advertising in London. "I feel much more relaxed in the week before my period, and I even like the oil's nutty taste."

There are plenty of anecdotes like these that attest to the therapeutic power of Hemp. Packed with digestible protein, vitamins and essential fatty acids, Hemp has been described as one of nature's most perfectly balanced foods. Grown throughout the world for thousands of years, it has enjoyed a considerable revival since the 1990s when it was reintroduced as a commercial crop in Europe. Hemp cultivation in Britain doubled between 1990-1997.

Although many people swear by Hemp, hard facts about its health-giving properties have been hard to come by until now. A team of scientists in Finland has conducted the first clinical trials, which show that Hemp oil can have dramatic effects.

The study, conducted at the Departments of Pharmaceutical Chemistry and Clinical Nutrition at the University of Kuopio, involved a group of 14 healthy volunteers taking a daily dose of Hemp Seed oil for four weeks. All kept detailed food diaries and were told to decrease their intake of saturated fats throughout the study so as to get clear results about levels of fats in the blood. After an appropriate break, they were asked to follow the same regime with linseed oil.

What researchers found was that Hemp Seed oil, as well as containing substantial levels of important essential fatty acids, considerably boosted the level of gamma-linolenic acid (GLA) in the blood. GLA has a potent anti-inflammatory effect, which may help to explain why it eases the pain of eczema.

Dr Jace Callaway, who headed the Finnish project, believes that there is likely to be a link. "Increased serum levels of GLA might help explain some of the numerous anecdotal reports of seemingly miraculous cures from people taking Hemp Seed oil, particularly those suffering from chronic health problems such as allergies, dry skin, slow wound healing and even rheumatoid arthritis." Linseed oil did not have the same effect, actually reducing levels of GLA in the body.

Hemp Seed oil contains the same potent essential fatty acids found in evening primrose oil, which is also used to relieve the symptoms of PMT.

Hemp does not have to be consumed just as cold oil. Like soybeans, Hemp Seeds can be made into many different food products. Crushed seeds can be used as flour to make bread, cakes, pasta, and biscuits. In addition, the soaked seeds can be made into "milk", ice cream and non-dairy cheeses.

Confusion often arises about the difference between Hemp and illegal cannabis. Hemp is a variety of the plant species Cannabis Sativa, but it has negligible psychoactive properties. You would have to drink about a litre of Hemp Seed oil to feel any effect.

Nutritionist Lorraine Perreta recommends Hemp Seed oil to anyone who wants to make sure they have a balanced diet - and a glowing complexion. "It literally lubricates from the outside in," she says. "Imagine having a moisturiser that works from beneath the skin." It is also possible to grind up the seeds and use the mash as a skin exfoliant.

Hemp Seed is also easy to digest, making it ideal for people suffering from gut and bowel problems. A recent report, funded by the Canadian government, says that 66 per cent of Hemp protein is high quality, the highest percentage of any plant source. Hemp also contains three times as much vitamin E as flax.

While Hemp Seed is a powerful healer, it is fragile. The essential fatty acids it contains are easily damaged if exposed to light, air or heat. So nutritionists recommend that Hemp Seed should never be cooked at high temperatures and is best eaten raw.