Hong Kong - Hong Kong health officials issued a warning Wednesday after they said a teenage girl became mentally ill after taking slimming pills she bought over the internet.

The 17-year-old became paranoid, began hallucinating and having suicidal thoughts after taking the pills named "Show Party," they said.

She was admitted to hospital after she began harming herself, the Department of Health said. Her mental state was said to be unstable.

Tests showed the pills to contain a banned ingredient called phenolphthalein, which was once used for treating constipation but has been banned for its cancer-causing effects.

The pills also contained a substance called sibutramine, an appetite suppressant that can lead to high blood pressure, psychosis and convulsions.

A Health Department spokesman urged people to stop using the product immediately and see a doctor if they felt unwell.

"Weight control should be achieved through good diet and appropriate exercise," the spokesman said. "They should consult health-care professionals before using any medication for weight control." (dpa)