Abuse of amphetamine derivatives such as 3,4methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) is an important issue in current forensic practice and fatalities are not infrequent. Therefore, we investigated an immunohistochemical method to detect the amphetamine analogues MDMA and MDA in human tissues. For the staining procedure, the Catalysed Signal Amplification (CSA) method using peroxidase (HRP) provided by Dako ® and specific monoclonal antibodies were used. Appropriate controls for validation of the technique were included. The distribution of these designer drugs was studied in various brain regions including the four lobes, the basal ganglia, hypothalamus, hippocampus, corpus callosum, medulla oblongata, pons, cerebellar vermis and, additionally, in the pituitary gland. A distinct positive reaction was observed in all cortical brain regions and the neurons of the basal ganglia, the hypothalamus, the hippocampus and the cerebellar vermis but in the brainstem, relatively weak staining of neurons was seen. The reaction presented as a mainly diffuse cytoplasmic staining of the perikaryon of the neurons, and often axons and dendrites were also visualised. In addition, the immunoreactivity was present in the white matter. In the pituitary gland, however, distinct immunopositive cells were observed, with a prominent heterogeneity. The immunohistochemical findings were supported by the toxi-cological data. This immunostaining technique can be used as evidence of intake or even poisoning with MDMA and/or MDA and can be an interesting tool in forensic practice when the usual samples for toxicological analysis are not available. Furthermore, this method can be used to investigate the distribution of these substances in the human body.