Its supposed medicinal qualities have been in demand for two millennia. Used by the Romans to treat the victims of snakebites and sickly children, legend has it that the white veins of milk thistle's leaves were created from drops of milk shed by the Virgin Mary.

Marketed as a liver tonic more than half a century ago, capsules made from the plant extract have sold steadily for decades. But now a new generation of partygoers, desperate to avoid the aftermath of festive over-indulgence, are discovering the plant, which is related to the daisy family and is native to the Mediterranean region.

Supermarkets and pharmacies report that demand for milk thistle before New Year's Eve is soaring as discussions on social networking sites extol its qualities as a potent hangover cure.

Tesco reports that sales of milk thistle capsules have risen 80% in the last few weeks.

"We hear from customers that milk thistle can work as a hangover cure and that appears to be borne out by our rising sales figures over the last few Decembers," said a spokeswoman for the supermarket chain.

"This year we are seeing a record level of sales and we have had to order in extra stock to make sure we have enough, especially with the new year a few days away."

Hangover salvation does not come cheap: a pack of 30 milk thistle capsules costs £13.95 at Tesco.

Milk thistle's active ingredient is silymarin, which is commonly recommended for liver and gallbladder disorders. But experts are divided over the plant's its medicinal qualities. Some research has suggested it can help treat alcohol-related liver disease, but other studies show it results in no improvement in liver function.

• Read our interactive guide to hangover cures