Four types of aescin that are available on the pharmaceutical market, beta-aescin crystalline, beta-aescin amorphous, beta-aescin sodium and aescin polysulfate, have been analyzed for their cytotoxic effects on human colon adenocarcinoma (LoVo) and doxorubicin-resistant human colon adenocarcinoma cell lines (LoVo/Dx). Their cytotoxic activities were evaluated by sulforhodamine B (SRB) and methyl tetrazolium (MTT) assays. All four types of aescin exerted strong dose-dependent cytotoxicity to LoVo and, to a lesser degree, LoVo/Dx cell lines. The IC50 value for the LoVo/Dx cell line was higher, but still dose-dependent. Results from both assays demonstrated that p-aescin crystalline has the most cytotoxic activity toward human colon adenocarcinoma cell lines.