In addition to DPIA (bis-amphetamine or di(beta-phenylisopropyl)amines), MDP2P and 1-benzyl-3-methylnaphthalene were analysed in ecstasy tablets. Little information is available on the risks of these synthetic by-products, and the interaction potential between these synthetic by-products and MDMA is completely unknown. MDP2P(3,4-methylenedioxy-phenylpropan-2-one) is a precursor substance for the synthesis (production) of MDMA. This is an indication of an incomplete synthesis process. The risks and side effects of this substance are unknown and there is no information on mixed use with MDMA. Whether and how MDP2P influences the risk of consumption cannot be assessed.