Conclusion 

The Tylenol murders were a terrible set of untargeted murders, where the killers poisoned some Tylenol bottles, there were some cases of medicine based murders before these, but there is no evidence that it was the same people. Of course, the media, public, and the Johnson & Johnson company, the people who make Tylenol, thought this was terrible. So, all Tylenol was brought back to the company, then, the company changed how they made and distributed Tylenol, which most people enjoyed, but some people found it restrictive. So, in conclusion, this terrible event changed how Tylenol was made and distributed.