Drug alert: The four slimming products in question include a ruby capsule claiming to contain bitter melon ingredients, Miyura Fit'x Capsules, an orange and white capsule, and a pearl-white capsule.

People should not buy or take four slimming products which have been found to contain undeclared Western medicine ingredients - phenolphthalein and sibutramine - that may cause serious side effects, the Department of Health says.

The products concerned include a ruby capsule that claims to contain bitter melon ingredients, Miyura Fit'x Capsules, and two unknown capsules - an orange and white capsule, and a pearl-white capsule. They were found for sale on an Internet website.