[en] Tritiated water (HTO) injected intraperitoneally to Swiss albino mice at the rate of 370 kBq (10 μCi)/g body weight has been found to cause certain alterations in blood parameters 1, 5, 7 and 15 days post injectionem. Leukocyte count dropped significantly post treatment. Differential leukocyte counting showed lymphocytes to be most affected which were reduced by 38.29% on 5th day p.i. Erythrocyte count, haemoglobin and haematocrit values though showed no significant changes at early intervals, these values were significantly lower at later intervals than those of control. (author)