Not exactly a drug, but during animal testing of saccharin in the 1970s, saccharin was found to induce bladder cancer in mice in high doses. However, the mechan

Not exactly a drug, but during animal testing of saccharin in the 1970s, saccharin was found to induce bladder cancer in mice in high doses. However, the mechanism of action was later found to be specific to rodents and not applicable to humans.