The Chicago Tylenol murders were a series of poisoning deaths resulting from drug tampering in the Chicago metropolitan area in 1982. The victims had all taken Tylenol-branded acetaminophen capsules that had been laced with potassium cyanide. Seven people died in the original poisonings, with several more deaths in subsequent copycat crimes. The incidents led to reforms in the packaging of over-the-counter substances and to federal anti-tampering laws.