Homeopathy
“Like cures like” was the rallying cry of the homeopaths, who believed that the human body knew how to best cure itself. If one’s body reacted to something in a certain way, it was because it was fighting off the effects; stimulating it to create a similar response would make the body heal faster.
However, too much of a deadly substance could kill the patient, so homeopaths made sure to dilute the various materials used in treatment by factors of 10 or 100. Critics of homeopathy often stated at that point there was no trace of the substances left, which to them proved that homeopathy was mere “quackery.”

Homeopathy struggled to balance being accessible to the general public while also being esoteric enough to be profitable for homeopaths. One solution was making recipes available to all but obfuscating them behind a number assignment. People at home could look up their symptoms, then find and order the corresponding numbered treatment.

Belladonna (from the deadly nightshade plant) is high in the alkaloid solanine, which can cause headaches and fevers. Following the doctrine of “like cures like,” belladonna was thus sometimes used to treat headaches.

As homeopathy became more standardized, companies began to sell pharmaceutical preparations wholesale to homeopathic practitioners.

Dr. James Sanson Read (1840-1933) was an 1869 graduate of the Homeopathic Medical College of Missouri. His notebook shows the experimental nature of this practice, as these homeopathic prescriptions recorded in the notebook were often edited or updated with information about the effects noted on patients. Homeopathy preferred to test remedies on healthy people in order to accurately gauge the effects on the human body.