ObjectiveThis study investigates the therapeutic effects of colchicine and melatonin on endometriotic implants in an experimentally created endometriosis model in rats. Study designForty-four adult female Wistar albino rats weighing between 260 and 300 g, 8 weeks old, were selected for the study. The unilateral uterine horn of rats with a bicornuate uterus was excised for 1 cm, washed with sterile saline, incised longitudinally, and the endometrium was exposed. A 0.5*0.5 cm endometrial tissue sample taken with a scalpel was implanted with suturing (4/0 Vicryl) to the abdominal wall. Forty-four rats were divided into four groups. Group 1 was randomized as the endometriosis group (control), Group 2 as endometriosis + colchicine treatment, Group 3 as endometriosis + melatonin treatment, and Group 4 as the endometriosis + melatonin + colchicine treatment group. The colchicine (Sigma Chemical Co., St Louis, Missouri) group was administered orally at a dose of 0.1 mg/kg, and the Melatonin group orally at a dose of melatonin (20 mg/kg per day). Treatment continued daily for 30 days. ResultsIn the post-treatment focal diameter measurements, the endometrial focal diameter in the colchicine and colchicine + melatonin group was significantly lower than the control group (p=0.026). Bcl-2 levels of the colchicine group were lower than the control group and the melatonin group (p=0.021). ConclusionColchicine and melatonin reduce adhesion to the peritoneal surface in ectopic endometrial cells. It also acts by increasing apoptosis and decreasing cell survival.