Sherif Olagunju, deputy head of the Lagos Central Drug and Vaccine Laboratory, sighs as he spreads out a gruesome collection of counterfeit medicines on his desk. Despite tough efforts in Nigeria to clamp down on fakes, recent hauls by his agency highlight the challenge they face.

He points to a bottle of Coflin cough mixture with a corroded cap and congealed contents; a packet of the antibiotic Septrin with no manufacturer's details; and a box of Ephedrine, a stimulant, that his analysis reveals to have less than three-quarters of the "active ingredient" needed to make it work effectively.