Bloodletting was dismissed in the 1870s. The first double blind rct was 1943.

Additionally, we use leeches for certain situations.

In the last 25 years leech therapy has made a comeback in the area of microsurgery and reimplantation sur­gery. Hirudo medicinalis can secrete several biologically active substances including hyaluronidase, fibrinase, proteinase inhibitors, and hirudin, an anticoagulant.

The leech can help reduce venous congestion and prevent tissue necrosis. In this way it can be used in the postoperative care of skin grafts and reimplanted fingers, ears, and toes. Because of concern regarding second­ary infections a “mechanical leech” has been developed at the University of Wisconsin.

I mean, bloodletting is rarely a valid treatment, and leeches can be good for it. The issue was more that it was overprescribed.

What's absolutely insane about it is that we literally got here by accident. Some homeopathic crank was selling diluted poison water to people, so he created a double blind test to prove his "medicine" was actually better than doing nothing and telling someone they would feel better, which ended up proving him absolutely wrong conclusively along with creating the wellspring of all medical advancement in the last century.

Behind the bastards did a series on the guy who invented this, and how he was a charlatan who's only achievement was creating the means of proving himself wrong lmao Added a link if you want to check it out