Four kinds of nucleic acid precursor (ATP,GMP,Adenine,Thymine) were injected intramuscularly into mice within 1h after 1050cGy whole-body γ-irradiation. Four days later,the mice were sacrificed and about 2cm long segment of duodenum, jejunum and ileum were dissected respectively for crypt survival assay using the technique of crypt counting per unit area. The results indicated that about 20% increase in crypt survival has been observed at each intestinal segment of mice receiving the nucleic acid precursor injection as compared with that of irradiated control. Meanwhile,the gross appearance of the samll intestine looks comparatively normal as well. From the results obtained both in this paper and in our previously published papers, which have been listed in detail in this paper, we propose that the nucleic acids (DNA,RNA) and its precursors (e.g. ATP, being used currently in clinical practice) can be used as one of the measures in the treatment of intestinal radiation damage induced by a large dose whole-body or abdominal irradiation.