Over an average human’s lifetime they are most likely to be prescribed and take more than 14,000 pills. Anti-depressants, antibiotics, cholesterol lowering tablets, painkillers, even tablets to extend youth and improve sexual performance in bed. These drugs perform small miracles daily, but how much is really known about them? Drug discovery often owes as much to accidental discovery as to science, and that means much is learnt about how medicines work, or even what they do, as they’re taken. By investigating some of the most popular pills people pop, Horizon asks, how much can they be trusted to do what they are supposed to?