公平交易法第二十四條：「除本法另有規定者外，事業亦不得為其他足以影響交易秩序之欺罔或顯失公平之行為」，不但文義模糊，更因其屬於「概括條款」，僅在公平法其他規定之構成要件未能符合時，方能適用之。而美國聯邦交易委員會法 (Federal Trade Commission Act) 第五條明文禁止「以不公平競爭方法，以及不公平或欺罔之行為或慣行從事式影響商業」(Unfair methods of competition in or affecting commerce, and unfair or deceptive acts or practices in or affecting commerce)。兩者條文在文義上相當接近，因此，作者試就前開美國法之文義規定、實務經驗以及學說，間釋聯邦交易委員會法第五條之真義以及適用範圍，尤其著重在該法與其他相關法律 (主要是其他反托拉斯法) 之關係。 本文發現聯邦交易委員會法第五條一方面可用以補充其他反托拉斯法之實體上漏洞。另一方面，由於該法係由聯邦交易委員會此等獨立機關 (independent agency) 執行之，性質上屬於行政管制。因此，與藉由刑罰或民事制裁手段控制，依賴、法院執行的其他反托拉斯法，更產生競合關係。尤有甚者，該法更有直接保護消費者之目的，為其他反托拉斯法所不能及。總之，聯邦交易委員會法第五條之適用範圍極為廣泛。 但鑒於中美兩國整體規範架構與執行體系不同，作者認為，公平交易法第二十四條目前之適用範圍有過廣之嫌。加上在公平法修正採取「先行政後司法」原則後，公平法之規範均由同一主管機關負責執行，公平會更有必要細膩地區分第二十四條與其他條文之界限，務使公平法第二十四條能夠成為真正的「補充條款」，而非無視於其他規定構成要件存在的「帝王條款」。

Article 24 of the Fair Trade Law is general and ambiguous clause, which serves as a "catch-all" as well as supplemental function. How to solidify and categorize the clause is a significant task for practitioners. Because Section 5 of the Federal Trade Commission Act of the United States Prohibits "unfair methods of competition in or affecting commerce, and unfair or deceptive acts or practices in or affecting commerce" and is similar to Article 24, the author explores the American experience and proceeds with some comparative research to be used as references for the Fair Trade Commission and the Administrative Court. The author found that the applicable scope of Section 5 of the Federal Trade Commission Act is very broad and overlapping with other antitrust laws. However, for the different statutory regime and enforcement mechanism, the applicable of Article 24 should be narrower than Section 5 of the Federal Trade Commission Act. In the United States, the different antitrust laws are enforced by separate agencies and have distinct penalties. The Sherman Act is enforced by the Department of Justice and the Federal courts and the Federal Trade Commission Act is enforced by an independent agency-the Federal Trade Commission, which has distinct constitutional status and broad authority. In Taiwan, however, there is only one Fair Trade Law and the Fair Trade Commission is the sole enforcement agency. Therefore, the author argues that the Fair Trade Commission should narrow down the applicable scope of Article 24, making it as the true "supplemental" clause.