During the 1982 Chicago Tylenol murders, cyanide contaminated the capsules.
Seven people in the Chicago area died after taking Extra-Strength Tylenol capsules that had been removed from store shelves, poisoned with potassium cyanide, and returned. The tampering occurred outside the manufacturer’s normal production process, making the case a criminal product-tampering incident rather than a conventional manufacturing defect.
Johnson & Johnson and its subsidiary McNeil Consumer Products issued a nationwide recall and introduced tamper-evident packaging, including foil seals and other safeguards. The crisis helped drive the development of federal tamper-resistant packaging requirements for over-the-counter medicines.
The case is often confused with a later Tylenol recall involving manufacturing problems. The 1982 deaths were specifically linked to deliberately poisoned capsules, and no perpetrator has been convicted of the murders.