In September and October 1982, the Chicago area experienced a cluster of sudden deaths tied to Extra-Strength Tylenol (acetaminophen) capsules. Several individuals who had purchased Tylenol from retail stores died after ingesting the drug; autopsies found lethal doses of potassium cyanide. The deaths led authorities to conclude that Tylenol bottles had been tampered with after leaving manufacturer facilities and after retail shelving, marking one of the first widely publicized incidents of retail product tampering and mass poisoning in the United States. The initial deaths occurred in late September and early October 1982. Victims included adults who had bought Tylenol at different stores and consumed the medication at home. Investigators found that in several cases the tampering involved replacing capsules or adding cyanide to loose capsules in bottles; some containers showed evidence of resealing. The apparent randomness of the victims—different ages and backgrounds, unconnected social ties—heightened public alarm. The Chicago Police Department, the Federal Bureau of Investigation, the Food and Drug Administration, and the manufacturer Johnson & Johnson all became involved in the investigation. Authorities urged consumers to stop using Tylenol and to check their medicine cabinets. Retailers pulled Tylenol from shelves in affected areas, and Johnson & Johnson issued press statements advising consumers and working with regulators and law enforcement. The case generated intense media coverage and spurred a nationwide recall of Tylenol products. In a highly publicized move, Johnson & Johnson offered rewards for information and cooperated with law enforcement. The outbreak of poisonings prompted broader public and regulatory scrutiny of the safety of over-the-counter drug packaging and retail security. No individual was ever convicted for the cyanide poisonings linked to the Tylenol bottles. A man named James William Lewis was convicted of an extortion attempt related to the case—he mailed a letter to Johnson & Johnson demanding $1 million to stop the murders—but he was not charged with the actual poisonings. Over subsequent decades, several suspects and theories have been investigated, but the primary perpetrator of the tampering has not been conclusively identified in court. The immediate public-health and industry consequences were significant. The Tylenol case accelerated development and adoption of tamper-evident packaging across the pharmaceutical industry, including sealed caps, foil seals, and other barriers intended to make post-manufacture tampering more detectable. The U.S. Congress passed the Federal Anti-Tampering Act in 1983, making product tampering a federal offense and increasing penalties. Regulators and manufacturers also refined product recall procedures and consumer advisories. Beyond packaging and legislation, the 1982 Tylenol poisonings influenced how companies communicate with the public during crises; Johnson & Johnson’s response—issuing warnings, cooperating with authorities, and recalling products—has been studied in business and public-relations literature as an early example of corporate crisis management. Although the direct criminal case remains unresolved, the Tylenol murders of 1982 had lasting effects on consumer safety practices, packaging standards, and legal approaches to product tampering, shaping how pharmaceuticals and other retail goods are protected and monitored in the decades since.