Using a basic food-reward system, normal household dogs were trained to detect both lung and breast cancer with 90-100% success rate when checked by biopsy-confirmation, only by smelling patients breath. This also after only a few weeks of training.
Bootleggers during Prohibition added an agent to their “patent medicine” that paralyzed its users partially to fully; there were approx. 50,000 victims. Those able to walk had a distinctive gait known as Jake leg.
As recently as 1985, infants and children up to 18 months old were routinely operated on without anesthetic, because it was believed that they could not feel pain.
Ketchup was sold as medicine in the 1830’s