Treatment of childhood asthma.

reasonable to expect, a fairly large number of small gastrointestinal bleeds then those who were alerted about what to look for could expect to detect a few more. Aspirin prophylaxisis is only recommended to be undertaken on medical advice. Presumably most doctors giving such advice would wam the patient of possible gastrointestinal bleeding and give advice on reporting it, if it occurs. The control groups would not be expected to have had similar advice. John Weil and colleagues could throw light on whether this confounding factor could be material to their results, by showing the breakdown of melaena and haematemesis in each of the three groups they studied.