Provided are compositions and methods for treating multiple sclerosis (MS). One embodiment of the disclosed method entails orally administering to a MS patient a first amount of a nonsteroidal anti-inflammatory drug (NSAID), such as aspirin, and a second amount of fumaric acid or an ester or a salt thereof. The NSAID is administered at from about 80 mg to about 500 mg per day and the fumaric acid or ester or salt thereof is administered at about 360 to about 420 mg per day. The compositions are formulated so that, upon oral administration to a subject, the both the NSAID and the fumaric acid or ester or salt thereof are released in the gastrointestinal track of the subject, and the NSAID is released at substantially the same time as, slower than, or later than the fumaric acid or ester or salt thereof. The delayed release of NSAID, it is herein observed, increased the bioavailability of the fumaric acid or ester or salt thereof.
