Diroximel fumarate, sold under the brand name Vumerity, is a medication used for the treatment of relapsing forms of multiple sclerosis (MS). It acts as an immunosuppressant and anti-inflammatory drug. Its most common adverse effects are flushing and gastrointestinal problems. Diroximel fumarate was approved for medical use in the United States in October 2019, and in the European Union in November 2021.