The toxicity of C. malayensis has undefined toxicity since Leaw et al. (2010) described as a new species. The previous study showed that C. malayensis (CAWD77), which was identified as C. monotis at that time, from New Zealand was mice toxicity at total cell number 2.1x 107 (Rhodes et al., 2000). Inversely, we showed that C. malayensis strain from Thailand was nontoxic. This may suggest that cell abundance of the strain used in this study may be not enough to result death in mouse.