https://www.mayoclinic.org/diseases-conditions/ulcerative-colitis/in-depth/ulcerative-colitis-flare-up/art-20120410
Ulcerative colitis flare-ups: 5 tips to manage them - Mayo Clinic
Try limiting or eliminating milk, yogurt, cheese, ice cream and other dairy products. This may help reduce symptoms of diarrhea, abdominal pain and gas.