Medicine at the time was not as advanced. Rush supported heroic medicine. This included things like bloodletting. People criticized Rush for this. It is now known to be dangerous. Rush also wrote case reports on infectious diseases like dengue fever. Rush believed that blackness was a curable skin disease. Today, this is considered false and wrong. Rush studied Native American health and why they got certain diseases. Rush also did a lot with mental health. He used mercury for mental problems. He developed occupational therapy and classified mental disorders. Rush treated addiction like a medical condition and not a sin. At the time, people had bad views about mentally sick people. Rush, however, said that mentally ill people were not inhuman animals. 