Abstract
The levonorgestrel-releasing intrauterine system (LNG-IUS), originally designed for contraception, has since been applied to various gynecologic diseases. This article summarizes the current status of clinical applications of LNG-IUS to the treatment of gynecologic diseases such as heavy menstrual bleeding, endometriosis, leiomyoma, adenomyosis, endometrial hyperplasia, and early-stage endometrial cancer.