摘要:In this study, the effects of boric acid (BA) andborax (BX) on the heart rate of rats treated with benzo(a) pyrene (B(a)P) and 3-methylcholanthrene (3-MC) were investigated. This research was con- ducted with the permission of Van Yüzünci Yil Uni-versity Animal Experiments Local Ethics Committee. Wistar albino rats weighing 250 ± 50 g were used inthe study and divided into nine groups, six in each group. Group I was assigned as the control group.B(a)P (100 mg/kg) was administered intraperitone- ally to Group 2 and 3-MC (100 mg/kg) to Group 3. BA only was administered to Group 4 at 300 mg/L in drinking water and to Group 5, BX only at 300 mg/L. Group 6 received B(a)P (100 mg/kg) + BA (300 mg/L) and Group 7 3-MC (100 mg/kg) + BA (300 mg/L). B(a)P (100 mg/kg) + BX (300 mg/L) was administered to Group 8 and 3-MC (100 mg/kg) +BX (300 mg/L) to Group 9. At the end of the 150th day, the rats were anaesthetised and their ECGs rec- orded. The heart rate (beats/min) was found to be sta- tistically significant in B(a)P, 3-MC and groups com- pared to the control group. It was found that the heart rate increased by 3-MC and B(a)P in the groups was regulated by BA and BX.