The aim of the Multiple Sclerosis Think Tank (Groupe de Réflexion sur la Sclérose en Plaques [GRESEP]), composed of hospital neurologists involved in the management of patients with multiple sclerosis, is to provide recommendations in response to clinical questions that are raised when managing these patients. After work done on the themes of useful serum testing with suspected multiple sclerosis, detection and management of cognitive disorders early in the course of the disease, and definition and early management of the disease, GRESEP wanted to develop recommendations on the management of multiple sclerosis (MS) relapse. Following a systematic analysis of the literature, the procedure of formal expert consensus enabled consensual recommendations among a working group, a rating group and a reading group to be written. Each recommendation is presented with its grade or the degree of consensus that it was accorded.