Abstract The cumulative figure for Lippes loop users reached 276,511 in Taiwan by the end of February, 1967. From a questionnaire survey carried out in April, 1967, 14 cases of proved displacement of the loop were reported by the 250 members of the Association of Obstetrics and Gynecology. This figure presumably includes the majority of such occurrences. Only 3 of the 14 cases had had insertion by a member of the Association. In 4 of the 5 cases seen by the authors, the site of perforation was on the uterine wall opposite to the direction of the uterine flexion. Four of the 5 patients reported pain and/or bleeding during insertion, suggesting direct injury to the uterine muscle wall at insertion. Two of the 5 patients had insertion mistakenly in early pregnancy, suggesting the vulnerability of the pregnant uterus. It is believed that it is better to have a loop inserted by a gynecologist after the uterus has recovered from the changes of pregnancy.