Antineoplastics are excreted into sewage, because patients often poorly metabolize them after administration or they are metabolized into more biologically reactive metabolites. There is little information on their biodegradation and toxicity in aquatic environments. Therefore, the biodegradability of the vinca alkaloids, and their toxicity towards wastewater bacteria were investigated in this study. The biodegradability of vindesine, vincristine, and vinblastine was examined in the closed bottle test (CBT). Additionally, the biodegradability of vinblastine as a model compound of the vinca alkaloids was tested in the Zahn-Wellens test (ZWT). The growth inhibition test with Pseudomonas putida was conducted, and a toxicity control in the CBT and the ZWT was used. The colony-forming units were monitored in the CBT; the test results for the biodegradability after 28 days were: 30% for vincristine, 20% for vindesine, and 10% for vinblastine. Therefore, none of the test compounds met the criteria for being readily biodegradable (> or = 60%). Vinblastine was biodegraded up to 18% in the ZWT after 40 days, and therefore, not inherently. Toxicity towards wastewater bacteria was not found.