Following the report of Dicke in 1950 that many child ren with the coeliac syndrome might be successfully treated with a diet free from wheat and rye flours, it was established that it was wheat and rye gluten which was harmful (Anderson et al, 1952 ; Dicke et al, 1953). Subsequent reports have confirmed the effectiveness of a gluten-free diet in nearly all children with the coeliac syndrome (Ross et al, 1955 ; Sheldon, 1955). In children with the coeliac syndrome who are intoler ant of gluten the enteropathy is thought to be the princi pal disorder. This is also true in adults with idiopathic steatorrhoea ; and in a proportion of such patients, as well as the children, the withdrawal of gluten from the diet leads to a return of normal intestinal function (Anderson et al, 1954 ; French et al, 1957). It has been suggested (Frazer, 1955) that "gluten-induced entero pathy " might be used as an inclusive term applicable to all patients, regardless of age, in whom a demonstrable enteropathy can be shown to be caused by gluten. It has not yet been established what level of gluten intake is without effect in a gluten-intolerant individual nor whether there is a dose/response relationship. It seems to be the general experience (Lawson, 1954) that a low level of gluten intake must be maintained for effec tive therapy, and for these reasons it seems advisable to make a gluten-free regime as complete as possible. Gluten intolerance appears to persist for a long time, and it may be necessary for a gluten-free diet to be con tinued indefinitely. There are several kinds of gluten, though all are plant proteins. In medical practice the word "gluten" is usually taken, as in this paper, to refer only to wheat and rye glutens. There is also a gluten in maize, but it seems to be harmless. The amount of protein in oats is low, and its importance in relation to gluten-induced enteropathy has not been finally evaluated. It is not ex cluded from a gluten-free diet at present, and we have not observed any ill effects from its inclusion. If in the future it appears that oats should be excluded, this could readily be done, because oat flour is rarely used except in porridge, breakfast and baby cereals, and certain cakes.