Singapore's health authorities Tuesday warned consumers against taking a traditional Indian remedy for piles known as Endopile Capsules.
The Health Sciences Authority (HSA) said a test of the drug, following a complaint, had revealed harmful amounts of lead and mercury.
The product has been recalled from the Singapore market. The HSA said the medicine is made by two firms in India.
The complaint came from a hospital that had treated a woman who had taken the pills.
Excessive amounts of lead and mercury pose serious health risks, as the toxic, heavy metals can accumulate in vital body organs, said experts.
Symptoms of toxicity include abdominal pain, vomiting, bloody diarrhoea, kidney damage and impairment of the nerves and mental functions.