Chicago Tylenol Murders


Example of the type of medication that was laced with cyanide back in the 1980s. The normal white shape of the pill made the disguise easier and effective.

Alizah Hashmi, In-Depth Writer

Between September and October of 1982, a spree of murder took place in the Chicago Metropolitan area. The brutal murders baffled the police since there were no connections among the victims. According to ABC7, during the autopsies, the medical examiner found traces of potassium cyanide in the bodies of the deceased. Though the cause of death was found to be poison, the police still had to figure out how all seven of these individuals were exposed to potassium cyanide.



Potassium cyanide is a white granular solid that is normally used during the extraction of gold and silver. The compound frees a chemical asphyxiant, known as hydrogen cyanide gas. According to the CDC, the chemical compromises the body’s ability to use the oxygen in the bloodstream. The lack of oxygen deprives and harms many vital parts of the body, such as the nervous and cardiovascular systems.



During the police investigation and further medical examinations, it was found that all the victims had taken an over-the-counter painkiller known as Tylenol. CBS News states that it was ultimately concluded that the Tylenol was laced with cyanide. 


Back in the 1980s, many over-the-counter medications did not have a seal or a covering preventing anyone from tampering with the medications. The perpetrator was easily able to enter his target pharmacies and manipulate the painkillers by adding lethal amounts of potassium cyanide to the medication. Given the side effects of this poison, the medical examiner was able to conclude a short yet painful death experienced by the seven victims.



Even 4 decades later, the perpetrator behind the ‘Tylenol’ murders is still unknown. However, the spree of their attacks allowed for some major changes to take place in the pharmaceutical industry.


Major pharmaceutical companies began to produce all their medications with tamper-proof seals. This seal prevented any type of manipulation of medication before its actual purchase. Any individual caught attempting to alter any type of medicine available to the public would be subject to harsher sentences. Pharmacies nationwide began to take security measures to keep over-the-counter medicines secure and safe for all to consume.


Even though basic safety precautions regarding OTC medications did not begin until after a major tragedy such as the Chicago Tylenol Murders, the changes the event initiated have prevented more souls from being unknowingly victimized.