The Pakistani national was arrested on suspicion at the Bandaranaike International Airport on Saturday after it was believed he was sumuggling heroin into the country.
He had arrived in Sri Lanka on board a Sri Lankan airlines flight from Pakistan, the police media unit said.
According to the police media unit the Pakistani man was checked by doctors last evening and 20 capsules were recovered from his stomoche with heroin.
The doctors suspect that more capsules with heroin still remain in his stomoche. The suspect continues to remain in hospital.