This from Wikipedia.
The Chicago Tylenol Murders were a series of poisoning deaths -- 7 of them -- resulting from drug tampering in the Chicago metropolitan area in 1982. The victims had all taken Tylenol-branded acetaminophen capsules that had been laced with potassium cyanide.
Before those horrific and senseless crimes, one couldn't verify that you were first to open an OTC medicine, a jar of peanut butter, jelly, milk carton, etc. The tamper-evident safety-seals to bottles and other packaging we have today is a result thanks to FDA and other agencies. Prompt and honest action by Tylenol contributed to it's becoming number 1 in sales of analgesics in the U.S.
The Tylenol murders have never been solved.
I, for one, am thankful for our watchdogs.