ABSTRACT
The radioprotective effect of cysteine on the haemopoietic and gastrointestinal syndromes, was investigated on forty five mature albino rats which divided equally into: two test groups and a control group. The rats of the two test groups were exposed to total body irradiation [2000 cGy]. Cysteine was given intraperitoneally[1 05 mg/gm.] to the rats of the second group, 15 minutes before exposure to the irradiation. Statistical analysis of the blood picture and jejunal crypts mitoses, showed a high significant decrease in the first group with a remarkable significant improvement in the second group [except for Hb concentration and RBCs count]. All these results are supported by the clinical observations, bone marrow cellularity and histopathological findings