We evaluated the clinical outcomes of using type 1 collagen gel after therapeutic resectoscopy; overall, 150 women aged > 20 who planned to undergo therapeutic resectoscopy were enrolled. The patients were randomly assigned to either of the anti-adhesive treatment groups: the type 1 collagen gel (Collabarrier®) (study group; N = 75) or the sodium hyaluronate and sodium carboxymethylcellulose gel group (control group; N = 75) after resectoscopy. One month after applying anti-adhesive materials, postoperative intrauterine adhesions were evaluated using second-look hysteroscopy; the incidence rate of postoperative intrauterine adhesions examined through second-look hysteroscopy showed no significant differences between the groups. There were no statistical differences between the frequency and mean scores of the type and intensity of adhesions in both groups. Finally, no significant differences in adverse events, serious adverse events, adverse device effects, and serious adverse device effects were noted between the two groups; type 1 collagen gel can be effectively and safely used in intrauterine surgery to minimize postoperative adhesions, thereby eventually decreasing the prevalence of infertility, secondary amenorrhea, and recurrent pregnancy loss in reproductive women.