Plenty of medicines existed before 1790... ...opium and extracts for pain relief, cinchona bark for malaria, cloves and clove oil for oral pain relief, I could

Plenty of medicines existed before 1790... ...opium and extracts for pain relief, cinchona bark for malaria, cloves and clove oil for oral pain relief, I could go on, but you could also Google this. And the fact that a "patent medicine" is a synonym in history for "snake oil" shows how little scientific rigour patents brought to medicinal development, and how the patent system was initially co-opted to lend an air of legitimacy to quackery.