Acanthamoeba castellanii (T4) was cultured with different concentrations of allitridium for 24 hours, and examined by transmission electron microscope. The results showed that the ultrastructure of Acanthamoeba trophozoites was destroyed gently at concentration of 50 microg/ml allitridium and seriously destroyed under the concentration of 500 microg/ml, indicating that allitridium is effective in destroying Acanthamoeba.