ＩＣＲ小鼠每周皮下注射２０ｍｇ／ｋｇ１，２－二甲肼（ＤＭＨ）共２０周，诱发大肠癌。对２个给药组分别从实验第１周和第１７周开始以１５ｍｇ／ｋｇβ－胡萝卜素灌胃，每周２次，至第２６周处死动物，前者小鼠大肠肿瘤发生率下降，大肠带瘤数减少，可溶性白细胞介素２受体（ＳＩＬ－２Ｒ）降低；后者小鼠大肠带瘤数也明显减少。以５ｍｇ／ｋｇβ－胡萝卜素灌胃，每天１次，第７天每鼠皮下注射ＤＭＨ２０ｍｇ／ｋｇ，２４ｈ后，小鼠大肠腺上皮细胞微核频率明显下降。 ICR mice were injected with 20 mg/kg 1,2-dimethyl-indole (DMH) subcutaneously every week for 20 weeks to induce colorectal cancer. For the two administration groups, 15 mg/kg β-carotene was intragastrically administered from the first week and the 17th week of the experiment, and the animals were sacrificed twice a week until the 26th week. The number of tumors decreased and soluble interleukin 2 receptor (SIL-2R) decreased; the latter also significantly reduced the number of colon tumors in mice. 5mg/kg β-carotene was intragastrically administered once a day, and DMH was subcutaneously injected at 20 mg/kg per mouse on the 7th day. After 24 hours, the frequency of micronucleus in the colonic epithelial cells was significantly decreased.