Envenoming by Protobothrops mucrosquamatus and Viridovipera stejnegeri accounts for the majority of venomous snakebites in Taiwan. We conducted a retrospective study to systematically examine the clinical manifestations and responses to antivenom therapy after P. mucrosquamatus and V. stejnegeri envenoming. Information on demographic characteristics, treatments, and systemic/local complications were abstracted from medical charts between 1991 and 2006. One hundred forty-nine patients with P. mucrosquamatus envenoming and 51 with V. stejnegeri envenoming were eligible for the final analysis, and they differed in terms of patient age, bite site, local bruising, proportion of patients needing >/= 3 vials of antivenom, and mean hospital stay. Univariate analysis revealed that P. mucrosquamatus envenoming had a higher risk of developing rhabdomyolysis, cellulitis, necrosis, and skin graft. Our findings suggested that P. mucrosquamatus envenoming was associated with a greater risk of severe clinical events, and monitoring for major clinical complications would be recommended.