A study on blood incoagulability due to snake bites was carried out in the Soudanian savanna of North Cameroon, in a provincial hospital receiving patients with severe envenoming coming from areas within 250 km of the hospital. Clinical and biological examinations were conducted on 57 voluntary patients to determine the aetiology of blood incoagulability. The aetiology of this syndrome is complex and seems to depend on the variability of venom components and/or the time between bite and hospital admission inducing a diversity of biological signs. Furthermore, the presence of bleeding and the 30 minute whole blood clotting test performed in dry tube were tested in view to propose simple diagnosis and monitoring indicators. It appeared that the combination of the two indicators allowed an early diagnosis of blood incoagulability and a valid monitoring test particularly well adapted to peripheral African health centres. The recommended treatment is intravenous immunotherapy using F(ab')2, renewed in case of persistence of bleedings or a whole blood clotting test higher than 30 minutes. However, the interval between immunotherapy administration renewals remains to be defined.