In 1943, David Karel de Jongh M.D. defended a Ph.D. dissertation on homeopathy, which he ended by concluding that homeopathy should be abolished. He based his judgment on his meticulous examination of many hundreds of articles and books and his experiences while working for quite some time in a homeopathic hospital in Utrecht, the Netherlands.
The dissertation has been is digitised in its entirety by Stichting Skepsis, because, according to secretary Jan Willem Nienhuys, ‘de Jongh’s conclusions [on homeopathy] are still as valid as ever’. A summary of de Jongh’s research can be read in English here, in Dutch here and in German here.