The adverse drug reaction profile of 3-fluoro-6-(4-methyl-piperazinyl)- 11H -dibenz[b,e]azepine ( fluperlapine -NB 106-689), a possible successor drug of clozapine, is presented based on, first, the results of the open multicentre trial of the AMDP group, and second, on two open multicentre trials initiated by the manufacturers. In general, side-effects of fluperlapine seem to be very similar to those of clozapine, i.e. anticholinergic and sedative effects as well as marked EEG-changes can be observed in most of the patients. However, in contrast to clozapine, so far no evidence for the occurrence of hypersalivation, or increase of body temperature has been obtained, although an increased white blood cell count around day 15 could be seen in quite a number of patients. Hypotensive effects were less than expected from corresponding trials with clozapine.