DiscussionOur results indicate that using the foam results in a good topical application of steroid to the lower rectum but that more proximal spread is limited and infrequent. One criticism that could be put forward is that we made no attempt to ensure that the rectum was clear of any hard faecal matter that might prevent the spread of the foam. All the patients, however, had loose stools, and the foam spread no further in them than in the controls.The aim of the study was simply to assess the extent of spread of the foam after rectal administration and not to attempt to compare the product with any other in terms of extent of spread or efficacy. Certain clinical implications, however, could not be avoided. On the basis of topical application alone the product is a rational treatment for only proctitis and mild distal ulcerative colitis. It would, however, seem illogical to use it for more proximal disease, and our clinical impression has been that under these circumstances it is less effective. If it is of benefit in more proximal disease this can be assumed to be only the result of absorption of the steroid from the foam by the rectal mucosa, any effect being that of systemic steroid. Of the clinical trials quoted by the manufacturer, only that of Scherl and Scherl4 attempted to differentiate between patients with proximal or distal disease. Unquestionably, however, the foam is more comfortable and easier to retain than a retention enema, and since the patient need not be immobilised, the foam obviously has a place in outpatient practice for patients with proctitis and distal ulcerative colitis.We wish to thank Professor B Pullan for his advice, and Stafford Miller Limited for supplying the Colifoam.