Background: An intravenous formulated extract of the venom of the wild toad Bufo bufo gargarizans Cantor or Bufo melanostictus Schneider, huachansu, is currently used in China for the treatment of lung, liver, pancreatic, and colorectal cancers. We performed a randomised, single-blinded, phase II clinical study of huachansu plus gemcitabine versus placebo plus gemcitabine in patients with locally advanced and/or metastatic pancreatic adenocarcinomas. Methods: Patients with tissue-proven locally advanced and/or metastatic pancreatic adenocarinoma were randomly assigned to receive either gemcitabine 1000 mg m−2 on days 1, 8, and 15 with huachansu 20 ml m−2 daily for 21 days (arm A) or placebo (arm B); treatment cycles were 28 days in length. Primary end point was 4-month progression-free overall survival (PFS); secondary end points were objective radiographical response rate (ORR), time to progression (TTP), and toxicity. Results: A total of 80 subjects were enrolled; 76 patients were evaluable (received at least 1 week therapy). Median overall survival was 160 days for arm A and 156 days for arm B (P=0.339); ORR was 9 and 3% in arms A and B, respectively (P=0.332), median TTP was 98 and 115 days, respectively (P=0.825); the median 4-month PFS was 99 and 98 days, respectively (P=0.679). Conclusion: Huachansu when combined with gemcitabine did not improve the outcome of patients with locally advanced and/or metastatic pancreatic cancer.