Colorectal adenoma (CRA) is a precancerous lesion for colorectal cancer. Endoscopic resection is the first-line treatment for CRA. However, CRA recurrence rate is high. This proposed study aims to determine if Chinese herbal medicine (CHM) reduces CRA recurrence.This project encompasses an observational, registry-based, cohort study and a nested qualitative study. The cohort study aims to include 364 postpolypectomy CRA participants at Guangdong Provincial Hospital of Chinese Medicine (GPHCM), China, with a follow-up phase of up to 1 year. In addition to routine care, these participants will receive a CHM treatment prescribed by experienced Chinese medicine (CM) clinicians. The CHM treatment encompasses CHM products and CHM formulae according to CM syndromes. The primary outcome is CRA recurrence rate at 1 year after enrolment. Secondary outcomes include characteristics of recurrent CRA, incidence of colorectal polyp (except for CRA), incidence of advanced CRA, incidence of colorectal cancer, improvement of gastrointestinal symptoms commonly seen in CRA patients, faecal occult blood test result, lipid level, fasting plasma glucose level, uric acid level, carcinoembryonic antigen, carbohydrate antigen 19-9, quality of life and safety evaluations. Logistic regression analysis will be used to explore the correlation between exposure and outcome. Qualitative interviews will be conducted among approximate 30 CRA patients from the cohort study and 10 CM practitioners in Department of Gastroenterology at GPHCM. Thematic analysis will be used to analyse qualitative data.Ethical approval has been obtained from the Human Research Ethics Committee (HREC) of GPHCM (YF2022-320-02) and registered at Royal Melbourne Institute of Technology (RMIT) HREC. The results will be disseminated in peer-reviewed journals and international academic conferences.ChiCTR2200065713.© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.