The severity of ulcerative colitis is determined by certain criteria. Ulcerative colitis can be classified as mild, moderate, or severe, which may guide treatment choices.¹

People who have mild ulcerative colitis may have:

• Fewer than four stools per day.
• No bleeding or a small amount of bleeding with stools.
• Normal or mild elevation of erythrocyte sedimentation rate (ESR).

People who have mild ulcerative colitis do not have fever, rapid heartbeat, or anemia.

People who have moderate ulcerative colitis have:

• More than four stools per day.
• Cramping abdominal pain and an urgent need to have a bowel movement.
• Mild elevation in erythrocyte sedimentation rate.

People who have severe ulcerative colitis usually:

• Have more than six stools per day (constant loose stools).
• Have frequent bleeding from the rectum.
• Have fever, rapid heartbeat, and anemia.
• Have an elevated erythrocyte sedimentation rate.
• Feel very ill.

Flare-ups can be so severe that they require hospitalization.