10 Deadly Things People Used To Think Were Harmless
6. Bloodletting
As far back as 1000BC, assorted quacks have held the risible belief that too much blood can be bad for you. A medieval doctor might have treated almost any medical complaint by fetching a knife, cutting a limb or two and letting out some of that bad, bad blood.
Naturally, theres actually not a great deal to be said for needlessly opening up one of your patients and bleeding them like a radiator. Invariably, patients would feel nauseous and lightheaded or, at worst, die of infection or blood loss. Obviously.