If you’ve ever purchased a bottle of Tylenol from your local pharmacy, you might have noticed a few unusual things about it. Every bottle of medication in the US comes with a tamper-proof seal, a piece of foil glued to the lid that indicates the bottle is safe to purchase. If someone has broken the seal, the bottle’s label tells you, don’t take any of the medication within.

The next thing you’ll notice is that the pills inside the bottle are caplets, not capsules. The medication is integrated with the structure of the caplet instead of sitting inside a capsule. These two safety features exist in over-the-counter medication because of a harrowing serial killer who terrorized the Chicago region in the early 1980s.

The Tylenol Killer

On September 29, 1982, a twelve-year-old girl named Mary Kellerman woke up feeling sick and took a Tylenol. She went to the bathroom, and her father, Dennis, heard something drop. He checked on her a few moments later and found her unresponsive and unconscious. She was pronounced dead at a hospital around 10 AM.

Later that day, Adam Janus also passed away after ingesting Tylenol. Adam’s brother, Stanley Janus, and his sister-in-law, Theresa Janus, returned home from the hospital later that day and took Tylenol from the same bottle. Both also passed away shortly after. At this point, investigators in Chicago realized that the deaths were all linked to the pain relief medication.


Investigators checked the Tylenol bottles in the Janus and Kellerman homes and discovered that someone planted cyanide in the capsules. Authorities warned residents in the Chicago area to discontinue taking Tylenol via loudspeakers and print ads. Johnson & Johnson conducted a widespread recall effort to pull the medication from store shelves to contain the damage.

Investigators believe the medications were tampered with after being placed on store shelves. The bottles containing cyanide were produced at locations in Pennsylvania and Texas, making it unlikely that anyone sabotaged them from the factory floor.


Investigators were never able to determine who was responsible for the poisonings. Though police made several arrests, the investigation never linked anyone to the Chicago incident. Hundreds of copycat crimes occurred throughout the US in the early- to mid-80s.

The incident led to increased safety measures for over-the-counter medications. Safety seals and caplets became the norm, replacing capsules in most non-prescription medications. The incident also resulted in legislation that made product tampering a federal crime. Sadly, the public may never know who was responsible for the infamous Tylenol poisonings.