Ulcerative colitis is a relapsing and remitting inflammatory bowel disease of the large intestine. Risk factors include recent Salmonella or Campylobacter infection and a family history of ulcerative colitis. Diagnosis is suspected based on symptoms of urgency, tenesmus, and hematochezia and is confirmed with endoscopic findings of continuous inflammation from the rectum to more proximal colon, depending on the extent of disease. Fecal calprotectin may be used to assess disease activity and relapse. Medications available to treat the inflammation include 5-aminosalicylic acid, corticosteroids, tumor necrosis factor–alpha antibodies, anti-integrin antibodies, anti-interleukin-12 and -23 antibodies, and Janus kinase inhibitors. Choice of medication and method of delivery depend on the location and severity of mucosal inflammation. Other treatments such as fecal microbiota transplantation are considered experimental, and complementary therapies such as probiotics and curcumin have mixed data. Surgical treatment may be needed for fulminant or refractory disease. Increased risk of colorectal cancer and use of immunosuppressive therapies affect the preventive care needs for these patients.