On 27 February 1998, the drug MBDB (N-methyl-1-(1,3-benzodioxol- 5-yl)-2-butanamine) became the first new synthetic drug to be submitted for risk assessment under the terms of the Joint Action concerning the information exchange, risk assessment and control of new synthetic drugs adopted on 16 June 1997 by the Council of the European Union. This publication consists of the main results of, and supporting documents from, a special risk-assessment meeting held at the EMCDDA in November 1998 with the participation of the Centre's Scientific Committee, experts from the 15 EU Member States, and representatives of the European Commission, the European Agency for the Evaluation of Medicinal Products (EMEA), London, and Europol.