Objective : We designed this study to analyse the anti-cancer effects of materials of green vegetable juice by using the natural standard methodology and apply the results to new studying and evaluating methods. Methods : We investigated the main stream of complementary and alternative medicine (CAM), the methodology of natural standard, guideline in CAM, and concrete 15 green vegetable juice in cancer therapy. Results : There are 15 graded materials of green vegetable juice that associated with cancer in natural standard contents. Most of them get grade C, unclear or conflicting scientific evidence. Conclusion : Natural Standard aims to provide high-quality, reliable information about CAM therapies to clinicians, patients, and healthcare institutions. We have to acquire more reliable evidence in future.