Taking weight-loss medicines containing orlistat can lead to severe liver injuries, the Department of Health warned today.

The US Food & Drug Administration advised consumers and healthcare professionals of the potential risk on May 26. Changes in product labels are required to reflect this rare occurrence.

The department has identified 13 cases of severe liver injuries reported in people taking orlistat. However, the causal effect has not yet been established.

In Hong Kong there are three registered products containing orlistat - Xenical, Zerocal and Alli. The former two contain 120mg of orlistat and can be sold on a doctor's prescription and dispensed under a pharmacist's supervision, while Alli contains 60mg of orlistat and can be sold under a pharmacist's supervision.

The department advised people taking these products to contact their doctor immediately if they develop liver problem symptoms, such as itching, yellow eyes or skin, dark urine, loss of appetite or light-coloured stools.