Knowledge concerning the relationship between multiple sclerosis and epilepsy is reviewed. Epidemiological studies have established that epileptic seizures are more frequent in multiple sclerosis than predicted by chance. Partial epilepsies with focal seizures often with atypical symptoms and with or without secondary generalisation are the usual pattern. In the survey special emphasis is laid on the direct correlation between paroxysmal phenomena and plaques now demonstrable by modern imaging techniques. These images have shown that epileptic seizures can be caused by cortical and subcortical lesions and by their accompanying oedema. We extend the review to non-epileptic paroxysmal symptoms, such as tonic spasm, which may be confused with epileptic seizures. As far as they are supported by data, recommendations for diagnosis and therapy are given. Open questions are identified and issues for further research are suggested.