HRccine was administered subcutaneously for 4 weeks to rabbits at dose levels of 300, 60 and 12 times the expected clinical dose to evaluate the subacute toxicity. There were no effects in clinical signs, body weight changes, food consumption, water consumption, urinalysis and blood biochemistry in any animals tested. In hematological examinations, decrease of lymphocyte counts and increase of platelet counts were observed in the medium- and high-dose treated groups. Absolute weights of thymus were tending to decrease, but no pathological changes were observed in microscopic examinations. The no-effect dose in subacute toxicity study of rabbits was considered to be 300 times the expected clinical dose.