Xue, a middle-aged female, was admitted to Jiangsu Province Hospital of Chinese Medicine for ulcerative colitis on January 19th, 2022. The patient was diagnosed with ulcerative colitis in Nanjing Hospital of Chinese Medicine Hospital on July 10th, 2021 and was discharged after treatment with Mesalazine sustained-release granules, dexamethasone tablets and montmorillonite powder. After discharging from the hospital, she regularly took Mesalazine sustained-release granules and took dexamethasone intermittently. The symptoms of the patient have been recurred in the last month, and was admitted to the hospital with : defecate 1-3 times a day, shapeless, with mucus, tenesmus, periumbilical abdominal pain, epigastric distension, fatigue, poor anorexia, low fever at night, body temperature fluctuating at 36.4-37.8 °C. Red tongue, with thin yellow coating, thready wiry pulse. Traditional Chinese medicine diagnosis: Chronic dysentery, Damp-heat syndrome of large intestine with spleen deficiency. Western medicine diagnosis: Crohn's disease; Anemia; Hypokalemia; Chronic gastritis; Liver cyst. Interventions: After admission, colonoscopy, small intestine magnetic resonance, enteroscopy have been done respectively, combined with her medical history and symptoms, a clear diagnosis of "Crohn's disease" was made. Consequently, anti-inflammation, anti-infection, rehydration and potassium supplementation, nutritional support, iron supplement to correct anemia, protection of intestinal mucosa, gastric acid inhibition to protect gastric mucosa was given successively. Combined with syndrome differentiation in traditional Chinese medicine, with the treatment principle of harmonizing Shaoyang and clearing dampness and heat, using addition and subtraction of "Haoqin Qingdan decoction". After the stated treatments, the patient's stool was formed without mucus, and didn't suffer from fevescence again.