An investigation is under way after two women were left seriously ill by a health drink contaminated with horse tranquillizer.

One of the women, aged 60, was reportedly left in a "vegetative state" after drinking the aloe vera juice contaminated with ketamine.

She and another woman, in her 40s, reacted to the drink which they are believed to have bought at a school fair in Leicester, England.

The 60-year-old is in Leicester Royal Infirmary where her condition is said to be satisfactory.

A spokeswoman for Britain's Health Protection Agency said: "The HPA is advising anyone who has a bottle of this liquid not to drink it and take it to the nearest police station. If they have drunk it they should seek medical advice immediately."

The daughter of the 60-year-old woman said she thought her mother was dying after she suffered a severe reaction to the drink.

The second woman, who fell ill on Friday, is in her mid-40s. She has since been discharged from hospital after being quickly treated with medication to counteract the ketamine.

Leicestershire police said the drink was called Gayatri aloe vera.

Detectives said consumers should treat with caution any juice labeled as aloe vera which is not purple.