The recent fentanyl dispute between China and the US adds the academic value to the efforts to examine the respective legal regime of public international law and the WTO law on narcotics trafficking. On the one hand, public international law offers a comprehensive framework to address narcotics trafficking but as demonstrated by Chinese proofs, its function is undermined by weak enforcement. On the other hand, there exist some useful mechanisms in the WTO law to combat narcotics trafficking but their weaknesses can also be easily spotted. More importantly, the alarm of the global threat of illicit trade is ringing, which requires our raising awareness to it. Recently, the UNCTAD and the OECD have already taken the initiative to discuss the collective actions, by means of conferences or reports, to deal with illicit trade. In the long run, it will be indispensable to establish an operational governance framework on the international level to effectively curb illicit trade.