1883, he and his colleagues found that the pathogen of cholera was Vibrio cholerae and its transmission route through water, food, clothes and other supplies. At the same time, the pathogens of amebic dysentery and two kinds of conjunctivitis were also found. In 1890, he proposed using tuberculin to treat tuberculosis. 1905 published a paper on tuberculosis control and won the Nobel Prize in Physiology or Medicine.

The Nobel Prize in Physiology or Medicine was awarded eight times in a hundred years: discovery of plasmodium and determination of malaria pathogen (1902, Ross, England; 1907, French Laveran); Discovering Mycobacterium tuberculosis and inventing tuberculin (1905, Koch, Germany); Determine the pathogen and transmission vector of typhus (1928, Nicole)； in French); Yellow fever virus was discovered (195 1 year, Sailor, Switzerland, South Africa); The tissue culture of poliovirus was successful (1954, Enders, Weller and Robbins)； from America); Discovery of hepatitis B virus surface antigen (1976, Bloomberg, USA); Discovery of Kulu disease virus (1976, Gechusek, USA); Discovery of prion (1997, Nell, Prusi, USA).