This study will enroll 60 patients with mild to moderate active ulcerative colitis as subjects. They will be randomly divided into two groups: the TCM group received QHQYP rectal instillation, while the control group received mesalazine enema. The treatment period for both groups was 8 weeks. The modified Mayo Activity Index will be used as the main evaluation index. Secondary evaluation indices will include the Underwater Endoscopic Severity Index (UCEIS) score, endoscopic Baron score, mucosal histological score (Geboes index), Chinese medicine syndrome efficacy evaluation, quality of life score, physicochemical indicators reflecting disease activity or remission, intestinal microbiota indicators, and changes in inflammation and immune-related indicators in colonoscopy biopsy tissues. Safety indicators were also monitored.

Inclusion Criteria:

1. Meets the diagnostic criteria for active ulcerative colitis, with clinical severity being mild or moderate and the lesion range being limited to the rectum or left colon and not extending beyond the splenic flexure.
2. Traditional Chinese medicine diagnosis indicates the presence of damp-heat syndrome in the large intestine.
3. Between the ages of 18 and 65, regardless of gender.
4. Informed consent and voluntary participation are required. The process of obtaining informed consent should comply with GCP regulations.

Exclusion Criteria:

1. Patients with severe disease condition.
2. Patients with infectious colonic diseases such as chronic schistosomiasis, bacterial dysentery, amoebic dysentery, intestinal tuberculosis, as well as non-infectious colonic diseases such as Crohn's disease, ischemic bowel disease, and radiation enteritis.
3. Patients with serious complications such as local stenosis, intestinal obstruction, intestinal perforation, rectal polyps, toxic megacolon, colon cancer, rectal cancer, and anal diseases.
4. Pregnant or lactating women.
5. Patients with severe primary heart, liver, lung, kidney, blood or other severe diseases that affect their survival.
6. Patients with disabilities as defined by law (blind, deaf, mute, intellectually disabled, mentally ill, physically disabled).
7. Patients with suspected or confirmed history of alcohol or drug abuse.
8. Other conditions that may reduce the likelihood of enrollment or complicate enrollment, as determined by the researcher, such as frequent changes in work environment that may lead to loss of follow-up.
9. Patients with allergies to two or more drugs or foods, or with a history of allergy to the components of this medication.
10. Patients currently participating in other clinical trials of medications.