Advertising in the medical and legal fields, which are among Korea's leading professions, has increasingly utilized major advertising platforms such as LawTalk and UNNI—two of the most prominent and contentious platforms in their respective fields. While it is generally unproblematic for professionals like lawyers and doctors to promote public interest through advertising on these commercial platforms, the creation of a profit-driven structure has the potential to undermine their professional ecosystems. This article explores the issues associated with advertising in the medical field through large commercial platforms, drawing on notable examples from the legal and medical fields in Korea. Specifically, we analyze two of the most popular yet controversial platforms in these sectors, LawTalk and UNNI. In Korea, the format and method of advertising are legal as long as they do not involve referring or soliciting clients, thereby making platform advertising lawful when used solely for that purpose. Nevertheless, it is crucial to prevent medical advertising platforms from establishing market monopolies by skirting various profit regulations and laws. In response to these concerns, the Korean Bar Association has prohibited all advertisements by platform companies. The medical community should closely examine the rationale and process behind this decision. Given the significant social influence of large corporate platforms and the unique social responsibilities of the medical and legal professions, future platform advertising should be subject to distinct legal and institutional regulations that differ from those applied to general services.