An. account is given on the value of stool examinations to the diagnosis of schistosomiasis mansoni; its positivity indicates active parasitism. Rectal biopsy was able to demonstrate the infection in 95% of intestinal cases and in 75% of hepatosplenic schistosomiasis; therefore, faeces examinations are necessary in order to diagnose a greater number of hepatoesplenic cases. The presence of dead eggs and/or granulomas and/or shells evidenciates the infection.