在世界反運動禁藥機構 (World Anti-Doping Agency, WADA) 公告之禁用清單中，meclofenoxate又名centrophenoxine，歸類於S6.B，屬於賽內期間禁用的特定性興奮物質。Meclofenoxate 是一種膽鹼性益智藥，也用作膳食補充品，容易造成運動員誤用風險，加上分析方法的不確定性，將影響運動員的參賽權益，因此進一步瞭解meclofenoxate 是重要課題。本文將介紹meclofenoxate 的臨床用途與作用機轉、不利檢測報告 (adverse analytical finding, AAF) 之案例、尿液檢驗方法對案例判決之影響、以及市售含meclofenoxate 之營養增補劑。Meclofenoxate 是dimethylethanolamine (DMAE)和4-chlorophenoxyacetic acid (4-CPA) 的酯類化合物，可有效增加大腦中乙醯膽鹼和磷脂醯膽鹼的含量，提升專注力且延長專注的時間。本文所摘錄之不利檢測報告案例皆與檢出高濃度的4-CPA 有關，由於涉及的運動員堅持未使用違規物質，經後續調查發現尿液中所出現的4-CPA 來自於洗髮用品與乳液中所使用的防腐劑chlorphenesin。雖然WADA 已針對meclofenoxate 誤判疑慮重新修訂判定方法，但在調查期間確實也已損害運動員的參賽權利。目前在臺灣並未核准生產含有meclofenoxate 的產品，但仍可透過跨國購物網站取得含有meclofenoxate 的營養增補劑，在不知情的情況下使用含meclofenoxate 相關的營養增補劑，易給運動員帶來極高的違規風險。透過本文所彙整之案例與判決資訊，可得知meclofenoxate 代謝物4-CPA 可能來自外用日常用品或化妝品，且因現行檢驗方法以及判定規則尚不夠周延，因此存在誤判的可能性，此情況將對運動員權益造成傷害。最終，本文建議當運動員接獲不利檢測報告時，應當冷靜思索，經確認沒有故意使用相關禁用物質的情形下，可尋求對運動禁藥領域熟稔的專業人士協助，針對非蓄意誤用或判定規則不完備的方向蒐集相關事證，以捍衛自身清白。

Meclofenoxate, also known as centrophenoxine, has been listed in the World Anti-Doping Agency (WADA) List of Prohibited Substances (S6.B specified stimulants) and prohibited incompetition. Meclofenoxate is a cholinergic nootropic used as a drug as well as a nutritional supplement, which may cause the risk of misuse by athletes. Moreover, uncertain analytical methods may affect the eligibility of athletes for competition. Therefore, it is an important issue to learn more about this substance. This article will introduce the meclofenoxate of clinical use and mechanism of action, adverse analytical finding (AAF) cases, urine analytical methods, and commercial nutritional supplements. Meclofenoxate, an ester of dimethylethanolamine (DMAE) and 4-chlorophenoxyacetic acid (4-CPA), has been shown to improve the performance on concentration via the increasing level of acetylcholine and phosphatidyl choline in the brain. AAF Cases described in this article are associated with the higher level of 4-CPA detected in urine. Since the athletes involved insisted on not using any prohibited substance, subsequent investigations found that the detected urinary 4-CPA came from chlorphenesin, a preservative used in shampoos and lotions. Although WADA has revised the testing methods and judgment rules in response to the misjudgment of meclofenoxate, it has indeed damaged the athlete's right to participate in competitions during the investigation. The production of products containing meclofenoxate currently is not approved in Taiwan, but nutritional supplements containing meclofenoxate can still be obtained through international shopping websites. It may bring risks of constituting an AAF to athletes who are unaware of using nutritional supplements containing meclofenoxate. Through the information of cases and judgments complicated in this review article, it has been recognized that the possible misjudgments may damage the rights of athletes because the current testing methods and judgment rules are not comprehensive. Finally, this article suggests that athletes should calmly confirm that no relevant prohibited substances are intentionally used when they receive an AAF. Athletes can seek the assistance of professionals who are familiar with doping issues, and prepare evidence associated with unintentional misuse or incomplete judgment rules to protect their reputation.