We have shown in this study that some drugs sold as 'legal' highs contain drugs that are controlled under the Misuse of Drugs Act (1971). Under current UK legislation, individuals purchasing legal highs that contained controlled drugs would be subject to the same penalties as if they had knowingly purchased a controlled drug. Dissemination of information on the harm associated with the use of legal highs should also inform individuals that they may be purchasing controlled substances and the potential legal consequences of this.