The proliferation of counterfeit and poor-quality medicines is a major public health problem, especially in developing countries lacking adequate resources to effectively monitor their prevalence. Industrialized countries are, for the moment, more affected by the phenomenon of adulteration of dietary supplements (DS) and herbal drugs. Counterfeit medicines (CM) and adulterated DS, in addition to the serious health risk they pose to populations, constitute a major challenge for analytical laboratories for their detection and characterization. Although seldom used in quality control laboratories, NMR is a technique of choice to analyze complex mixtures and to determine their different constituents. The aim of this article is to present several examples of the use of ¹H NMR as a first-line analytical technique for uncovering CM and adulterated DS. Studies on the quality evaluation of heparin, essential antimalarial medicines, drugs and DS intended to treat erectile dysfunction, slimming DS, anti-inflammatory DS, and some cosmetic creams are reviewed. The potential of isotopic NMR in the field of drug counterfeiting is also presented. Advantages and limitations of NMR are finally discussed.