The foil seals on medicine bottles were placed due to poisoning incidents. The Tylenol poisonings of 1982 were a widespread crisis that involved U.S. consumers dying or falling ill from Tylenol. It was later found that the bottles had been laced with potassium cyanide. To restore the faith of the public in the product and the company, Johnson & Johnson patented the seal to prevent further tampering incidents. This is also the thought behind the “Do not accept if seal is broken.” warnings that we see with other products.