Tecfidera (generic: dimethyl fumarate) is a prescription medication used to treat multiple sclerosis (MS). Tecfidera belongs to a group of drugs called fumaric acid esters. The exact way it works to treat multiple sclerosis is unknown.

This medication comes as delayed-release capsules to be taken twice daily. Swallow Tecfidera capsules whole.

Common side effects of Tecfidera include flushing (warmth and redness of skin), nausea, diarrhea, and stomach pain.