Trimeresurus popeorum, a dark green pit viper, is commonly found in Southeast Asia. This study describes the clinical picture and blood studies of 51 patients bitten by this snake. Affected limbs were swollen; and hemorrhagic blebs in fingers and toes were found in 12 patients. Lymphangitis was observed in 4 instances. Six individuals exhibited hypofibrinogenemia of 0–84 mg/dl, and 2 cases developed thrombocytopenia and bleeding. The presence of venom in the blood of these patients was demonstrated. Positive fibrin degradation products of 40–320 µg/ml were observed in 6 cases with hypofibrinogenemia, and in 8 other cases. Nineteen patients had short euglobulin lysis times of 51.8 ± 24.7 min. Hyperfibrinogenemia of 626.7 ± 288.9 mg/dl was found in 18 cases. Apart from bleeding, there were no systemic symptoms. Hypofibrinogenemia became normal in 3–12 days. The clinical course in all patients was uneventful, and none received antivenin.