In 11 patients with complex partial epileptic seizures stuporous states were observed during treatment with valproate (VPA) (2 cases), with VPA and phenobarbitone (PB) (4 cases), or with VPA, PB and a third anti-epileptic drug (5 cases). Based on 3 characteristic cases, an attempt is made to define the role of VPA, the nature of the stuporous states, and the origin of digestive disorders which often herald the onset of behavioural disorders. Several clinical studies have suggested the direct responsibility of VPA even if the adverse effects are potentiated by many other anti-epileptic drugs. Stuporous states are not due to VPA overdose and do not depend on the mode of administration. No correlation has been found between electroclinical signs and plasma or CSF levels of the different anti-epileptic drugs. Reported data and the present cases suggest a paradoxical epileptogenic role for VPA on complex partial seizures: there exists a close similarity of electroclinical findings between spontaneous epileptic seizures and stuporous states during DPA treatment. Digestive disorders appear to result from a central mechanism and not from digestive tract intolerance. In some cases, it is likely that partial seizures with digestive symptoms and signs do occur.