The goal of this clinical trial is to learn if Shenling Baizhu granules can prevent colorectal adenoma from coming back in people who had low-risk colorectal adenomas removed. The main questions it aims to answer are: * Can Shenling Baizhu granules lower the rate of colorectal adenoma returning after removal? * How safe is Shenling Baizhu granules when used long-term for preventing adenoma? * Which patients are most likely to benefit from this treatment? Researchers will compare Shenling Baizhu granules to no treatment to see if the medicine works to prevent adenomas from returning. Participants will: * Take Shenling Baizhu granules (6 grams, 3 times daily) or receive no treatment for 6 months * Have regular check-ups and provide blood, stool, saliva, and tissue samples * Get a colonoscopy after 3 years to check if any adenomas have returned * Fill out questionnaires about their symptoms and overall health throughout the study This study will include 624 adults aged 18-70 who recently had low-risk colorectal adenomas removed at participating hospitals. The total study duration is 4 years.