AIM: To introduce the basic methods of gray relational analysis (GRA) and to illustrate its applications in gastroenterology.METHODS: With the essential formulae of GRA and several typically practical examples, the procedure of GRA was introduced. Examples were drawn from the gastroenterological studies. Thus the trait of GRA could be demonstrated.RESULTS: The superiority of GRA in gastroenterological study was proved by the examples. CONCLUSION: GRA can be applied mechanically or flexibly in gastroenterology.