Therapeutic nihilism slowly faded in the 19th century as systematic reform of the medical education system took place, then reappeared in the 20th century in a slightly different fashion than prior. The aggressive empiricism of the 19th century enlightened the medical society of the need to thoroughly evaluate every aspect of clinical practice. Prior to the publication of rigorous research later in the 20th century, some physicians believed the most potent weapon for treatment was not medication, but the regulation of bodily secretions such as bloodletting, promotion of perspiration, or urination to regain the natural state of equilibrium. Ivan Illich was one of the ardent supporters of therapeutic nihilism. In his book "Medical Nemesis", Illich claimed that the great increase in life expectancy and public health experienced in his era was due to improved nutrition and sanitation, rather than innovation in drugs and medicines. He also believed there was an excess of physicians, surgeries and prescriptions. Therapeutic nihilists claimed such excess often led to malpractice and increase in iatrogenic (doctor-caused) injuries, accusing the physicians of creating even more illnesses.