Gas chromatography analysis of unadulterated illicit cocaine base samples usually showed the dominating presence of cocaine, frequently accompanied by very small but variable amounts of congeners. By using reference substances, the presence of cocaine, tropacocaine, anhydromethylecgonine, and trans-cinnamoylcocaine could be easily established. Three unknown substances identified in the chromatogram were analyzed by high-performance liquid chromatography. They were subsequently identified as norcocaine, N-benzoylnorecgnonine methyl ester, and N-formyl norcocaine. Their presence in the illicit cocaine samples is explained as a result of the permanganate bleaching procedure that is routinely performed as part of the illegal production protocol. 49 references and 12 figures (Author abstract modified)