Minimizing the Risk of Metachronous Adenomas of the Colorectum With Green Tea Extract -MIRACLE-

Inclusion Criteria: * Between 50-80 years of age * Histologically confirmed colorectal adenomas or serrated lesions removed during colonoscopy within the last 6 months * Good performance status (ECOG \< 2) at study entrance * Written informed consent. Exclusion Criteria: * History of hereditary nonpolyposis colorectal cancer (HNPCC) or familial adenomatous polyposis (FAP) * History of colon or rectal cancer, other concomitant cancers with the exemption of basalioma or curative treated cancers without actual anticancer medication. * Intestinal malabsorption, short bowel syndrome or surgical bowel interventions leading to malabsorption * Liver failure (hepatitis, cirrhosis, elevation of liver enzymes ALT, AST or bilirubin to more than 2.5 fold of the reference levels) * Inflammatory bowel disease * Regular intake of NSAIDs (also Cox2 inhibitors) for more than 3 months per year except of low-dose aspirin (100 mg per day) * Immunosuppressive medication * Impaired capacity to consent or who are impaired in swallowing a pill * Regular consumption of green tea extract as nutritional supplement (with a content of EGCG of more than 100mg per day) of longer than 6 months during the past two years * Allergic reactions towards green tea