Which is safe to take?

Let's admit it: many of us have congratulated ourselves, if a bit guiltily, for buying a counterfeit branded handbag or DVD, pleased to have paid so little for something that was almost as good as the real thing. Most consumers would not knowingly apply the same logic to the medicine they take—who wants imitation Viagra? But people around the world may be unwittingly buying fake pharmaceuticals all the same. A raid of a ramshackle warehouse in southern China's Guangdong province last month turned up plenty of evidence that brand-name drugs are not always what they seem. In the raid, Chinese police...