BACKGROUND Two clinical cases are reported of envenomation by the nose-horned viper (Vipera ammodytes ammodytes) venom of a 9-year-old boy and of an 84-year-old woman. METHODS Both patients had been bitten on their extremities by such a snake in August near Split, a town in southern Croatia. METHODS Clinical manifestation of envenomation was severe in the case of the boy, being characterized by a severe coagulopathy. This was only just apparent in the case of the elderly woman, who suffered extensive local edema and hematoma at the site of the bite, together with a neurotoxic effect-bilateral ptosis. This was the first occasion of thrombocytopenic purpura being observed in patients envenomed by nose-horned viper venom. This unexpected clinical finding was characterized by an unusually profound thrombocytopenia of 5 and 10 × 10/L platelets of the respective patients on their admission to the hospital, together with purpura, observed on the face and thorax of both individuals. In the most serious cases, such pathology can be life threatening if not promptly recognized and treated. METHODS The patients recovered quickly on receiving the specific antivenom along with all the usual supportive treatments. RESULTS No serious sequels were noticed at the moment of discharge. CONCLUSIONS Our finding constitutes an important message to clinicians to consider the possibility of such complications in the case of nose-horned viper envenomation.