Attachment Last Update June 1, 2021 Extension .pdf Print Code WI85-1138 Language English Creator Collaborative Inflammatory Bowel Disease Program Methotrexate is a treatment used to help Crohn’s disease or ulcerative colitis. This pamphlet explains what methotrexate (MTX) is, how well it works, side effects of MTX, who should not take MTX, and precautions.