Background Settlements between doctors and patients provide a solution to complicated disputes. However, some disputes may be renewed as a result of negligence by both parties. The purpose of this study was to review the legal issues that may potentially arise during the preparation of settlement agreements and to propose a list of requirements for ensuring the effectiveness of these settlement agreements. Methods Data from 287 civil cases concerning aesthetic surgery that took place between 2000 and 2015 were collected from a court database in South Korea. Factors that influenced the effectiveness of settlement agreements were analyzed. Results Among the 287 court precedents, there were 68 cases of covenant not to sue. Eighteen cases were dismissed because the settlement agreements were recognized as effective, and 50 cases were sent forward for judgment on their merits because the agreements were not recognized as effective. The types of surgery and types of complications were classified by frequency. We evaluated the geographical distribution of the precedents, the settlement timing, and the effectiveness and economic impact of the settlements. We found that there was no statistically significant relationship among these factors. Four major factors that made a settlement agreement legally effective were identified, and the data showed that fee-free reoperations were not considered by the court in determining the compensation amount. Conclusions When preparing a settlement agreement, it is advisable to review the contents of the agreement rather than to take the preparation of a settlement agreement per se to be legally meaningful.