In late September and early October 1982, a series of sudden deaths in the Chicago area were traced to Extra-Strength Tylenol capsules that had been deliberately contaminated with potassium cyanide. The first widely reported death occurred on September 29, when 12-year-old Mary Kellerman of Elk Grove Village, Illinois, died after taking Tylenol for a sore throat. Within days, six more people in the Chicago suburbs and nearby communities—ranging in age and background—died after ingesting the same brand. Investigators quickly identified that the victims had taken Tylenol capsules purchased at retail stores and that the capsules had been tampered with after leaving the manufacturer. The scale and apparent randomness of the poisonings generated intense media coverage and public fear. Authorities in the Chicago area and federal agencies, including the FBI and the Food and Drug Administration (FDA), launched a broad criminal investigation. Law enforcement officials examined retail outlets, distribution channels and manufacturer records while warning the public to avoid taking any Tylenol or similar over-the-counter capsule products until more information was available. Large numbers of consumers discarded capsule bottles and panicked lines formed at pharmacies seeking refunds or alternatives. Johnson & Johnson, the parent company of Tylenol maker McNeil Consumer Products, cooperated with investigators and moved quickly to recall Tylenol products from retailers nationwide. The company’s decision to remove millions of bottles from store shelves was unprecedented at the time for an over-the-counter medication and reflected both public safety concerns and pressure from authorities and the media. The case exposed vulnerabilities in the packaging and distribution of over-the-counter medicines. At the time, many products were sold in easily opened bottles without tamper-evident features, and capsules could be opened or replaced without obvious signs. In response to the murders and the resulting public outcry, manufacturers and regulators moved to implement new safety measures. Tamper-evident packaging—such as glued boxes, shrink-wrap seals, and foil or plastic seals over bottle openings—became industry standards. The FDA later issued regulations requiring tamper-evident packaging for many nonprescription drugs. Despite an intensive investigation that included interviews, forensic testing, and public tips, authorities never conclusively identified or convicted the person responsible for the original Chicago-area poisonings. Over time, various suspects were investigated, including individuals with access to retail stores or motive, but the case remained officially unsolved. The uncertainty left lasting public unease and frequent references to the case in discussions about product safety and criminal investigations. The Tylenol murders had broader consequences beyond packaging rules. Retailers and manufacturers adopted stricter quality-control and inventory-monitoring practices. Public awareness of the potential for product tampering increased, and consumers became more attentive to packaging seals and other indicators of tampering. The incident also influenced crisis communication practices: Johnson & Johnson’s response—swift recall and frequent public updates—has been studied as a case of corporate crisis management, even as it contended with intense criticism and legal exposure. Anniversaries of the 1982 poisonings regularly prompt retrospectives on how the events changed consumer protection. While the immediate deaths and the unresolved criminal mystery remain a painful chapter for victims’ families and for the Chicago area, the episode led to concrete regulatory and industry changes designed to reduce the risk of similar attacks on over-the-counter medications.