Abstract: We have studied the acute toxicity and mutagenicity of mycobacterial polysaccharide (MPS) injection.The LD₅₀ was higher than 46.4 ml/kg when intraperitoneal injection to both sexes of mice was made.No mutagenie effects were found in Ames' test and in analysis of sperm abervation of mice.While in micronucleus test of mice bone marrow, the proportion of micronucleus cell in group of high dose was singnificantly higher than that in group of negative control(P<0.01 ), but it was only 4.3‰ and still within the upper limit of normal-ity.Meanwhile, no increase of the proportion of micronucleus cell was found in group of middle dose (11.6 ml/kg), which was 1150 times more than that used in clinic.Thus, we think that MPS may have no risk leading to injury of chromosome in actual use.

Key words: mycobacterial polysaccharide, immunomodulator, toxicology, evaluation of safety