Darwin's illness revealed.

After returning from the Beagle in 1836, Charles Darwin suffered for over 40 years from long bouts of vomiting, gut pain, headaches, severe tiredness, skin problems, and depression. Twenty doctors failed to treat him. Many books and papers have explained Darwin's mystery illness as organic or psychosomatic, including arsenic poisoning, Chagas' disease, multiple allergy, hypochondria, or bereavement syndrome.