Amyotrophic lateral sclerosis (ALS) is a rapidly fatal degenerative disorder of the motoneurones which was without any effective therapy until 1997. Riluzole (Rilutek) has been the first patented drug used in its specific treatment. In order to evaluate the tolerability profile of this molecule, a Pharmacovigilance study was undertaken in the Department of Neurology B at the Montpellier University Hospital. A total of 153 patients were studied and all observed side-effects were listed in the French bank of Pharmacovigilance. Riluzole induced one or more adverse effects in 50.3 per cent of patients. The most frequent were gastrointestinal disturbances, hepatotoxicity and asthenia. Dermatological, haematological, neuropsychiatric and metabolic side-effects were also reported. This study shows an acceptable safety profile for riluzole. Due to its mode of action, riluzole could potentially be used in the treatment of other neurodegenerative diseases involving glutamate excitotoxicity. Subsequently, Pharmacovigilance will have to be carried out to establish the proper use of riluzole.