The purpose of this study was to validate a test for diagnosis and monitoring of hemorrhagic syndrome following viper envenomation in sub-Saharian Africa. A total of 276 patients treated at 7 health centers or hospitals in North Cameroon were included. Hemorrhage was observed in 144 patients (52.2%). Coagulation time was longer than 30 minutes in 196 patients (71%). Overall hemorrhage and/or prolonged coagulation time was noted in 223 patients (80.8%). Combination of these two findings was a reliable indicator for diagnosis and monitoring. Observation of one of these factors, i.e. hemorrhage or prolonged coagulation time, indicates immunotherapy using F(ab')2. This treatment should be continued until the indicator disappears and renewed in case of relapse.