Cannabis is an herbaceous flowering plant of the Cannabis genus (Rosale) that has been used for its fibre and medicinal properties for thousands of years. In recent decades medicinal cannabis has become legal in several jurisdictions and the possibility of legalisation is being explored in many more. This legalisation has opened the field of medicinal cannabis research. The biochemistry of cannabis is rich and varied including phytocannabinoids, terpenes and phenolics. Each of these metabolite classes contains individual compounds with biological activity. This chemical diversity and the interaction between molecules may underpin the ‘entourage effect’ that is believed to contribute to the medical efficacy of cannabis. In order to fully explore this biochemistry we have undertaken both targeted and untargeted metabolomic and volatolomic analysis of diverse cannabis strains. 70 diverse strains have been characterised using liquid chromatography mass spectrometry (LCMS), nuclear magnetic resonance (NMR) and gas chromatography mass spectrometry (GCMS). The chemotaxonomic relationship between the strains will be discussed. In combination with genomics these analyses offer the potential for ‘designer strains’ to be developed for particular medical applications.