Valid tests of anti-epileptic drugs presume prospective, long-term, controlled studies and standardization of history-taking and examination, treatment, and assessment of results (1). These concepts have been used as the basis of a multicenter trial in seven hospitals, which had the advantage that a representative number of subjects could quickly be obtained. Carbamazepin seemed to be particularly suitable for testing this method of assessment, both as an anticonvulsive and as a psychotropic, tricyclic antiepileptic drug (2, 3, 4, 6). In addition, it has unusual electroencephalographic effects and chemical structure (5, 7).The recording of the significant parameters used in trial comprised the general and the special history of the fits, enumeration of 15 different types of fits, neurological and psychological findings, numerous laboratory data, and a detailed EEG report. The layout of the trial enabled therapeutic efficacy to be assessed, both in the individual and in the total population, by contrasting it with a standard treatment defined in advance for each type of fit (diphenylhydantoine or primidone in grand mal and psychomotor attacks and succinimides in petit mal). The individual maximum dosis was considered to be reached, if either continuous absence of attacks or manifestation of toxic signs were observed. The first two illustrations (figs. 1 and 2) indicate the method of record-keeping by showing parts of the pro-formas used. The examples given of symptoms, of types, and of frequency of fits, demonstrate the aim, i.e., to obtain as much fine differentiation as possible in all areas investigated.The data were handled by means of a programme system (SEDAS) that had been specially developed for the evaluation of sequential data. A description in detail will be published elsewhere.By means of this method 1,205 diagnostic "cross-sections" of 182 patients were obtained in the seven hospitals between 1. 1. 1967 and 1. 7. 1969. Fig. 3 presents the distribution of the frequency of "cross-section" examinations. 80°/o of the patients had either grand mal or psychomotor fits or both types together. This is why the following statements refer to this group only. Out of the abundance of resulting data only the anticonvulsive effects, the accompanying and the side-effects have been touched upon here.* Carbamazepin = Tegretal®, Tegretol®.