What’s that in the airing cupboard? A pancake on steroids? A chamois leather that’s seen better days? No, it’s kombucha - a homegrown fungus that has won a worldwide reputation for its health-giving properties.

From its origins in eastern Asia around 2,000 years ago, kombucha’s fame has spread far and wide, mainly by word of mouth. Whether people call it the Manchurian mushroom, teekwass (in Russia), or olinka (in Moravia), they are all talking about the same thing - a slimy-looking fungus that is composed of several kinds of yeast and bacteria.

The “mushroom” is fermented by being floated in a large bowl of sweetened black tea left in a warm place. After about a week, the resultant liquid, which tastes of apple vinegar, is drained and sieved, and then drunk by the wine-glassful, several times a day. Making it yourself has its advantages - it costs next to nothing - but care has to be taken to keep it free from contamination. Some novices have been known to suffer upset stomachs.

Kombucha contains a complex range of B vitamins, usnic acid (an antibacterial agent), glucuronic acid (a detoxifier) and several other beneficial compounds.

According to believers, kombucha can help with digestive problems, immune deficiencies, arthritis, chronic fatigue syndrome, multiple sclerosis, skin diseases and all sorts of other ailments, aches and pains.

Kombucha can be bought in some health food shops, and it’s a measure of its global popularity, not to mention cult status, that in Beverly Hills it sells for $5 (Pounds 3) a pint.

In the week it takes to mature, the fungus also produces an offspring, which can be given to a friend. In the UK, the pass-it-on philosophy is encouraged by the Kombucha Network, a fraternity of fungus lovers, who can supply you with a starter kit.

To contact the Kombucha Network, send an SAE to PO Box 1887, Bath BA2 8YA