Gluten is a protein found in cereals such as wheat, barley and rye. For many people, gluten is not a problem, but for some, gluten consumption can lead to various health problems. The side effects of gluten consumption can be varied and include both digestive and extra-digestive symptoms. In this article, we will discuss what the side effects of gluten consumption are, what the causes are and what diagnostic methods and treatments are available for those suffering from gluten intolerance or coeliac disease.