The invention relates to the use of pentacyclic triterpene for the preparation of a pharmaceutical compound intended for the treatment of multiple sclerosis. Oleanolic acid (3ss-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpene acid present in a large number of medicinal plants. The invention relates to the pharmacological use of oleanolic acid either alone or combined with other substances in the therapy or prophylaxis of neurodegenerative diseases, such as multiple sclerosis. The applicants have found that the daily intraperitoneal administration of oleanolic acid significantly reduces the neurological and immunoinflammatory symptoms associated with experimental autoimmune encephalomyelitis, an experimental model of multiple sclerosis, delaying the onset and reducing the progression of the disease
