The Department of Health has found two slimming products, Super Fat Loss and Natural Slimming, to contain undeclared ingredients that can cause serious side effects.

Phenolphthalein and sibutramine were found in the products bought online.

Unsafe drugs: Slimming products Natural Slimming and Super Fat Loss contain undeclared ingredients that can cause serious side effects.

Phenolphthalein is used for treating constipation and has been banned for its cancer-causing effect. Sibutramine is used as an appetite suppressant for slimming with side effects including increased blood pressure and heart rate.

Products containing sibutramine must be registered and can only be sold on a doctor's prescription in Hong Kong and dispensed under a pharmacist's supervision.

People should not buy or use the products and should consult healthcare professionals if they want to lose weight. A balanced diet and exercise are crucial factors in keeping fit and healthy.