Unusual causes of occult bleeding from the gastrointestinal tract

The patient who presents only the signs and symptoms of microcytic anemia due to bleeding from the alimentary tract must be subjected to a very careful search for all information which might lead to a diagnosis, with special emphasis on history of drug ingestion and on those diagnostic procedures available for direct and indirect visualization of the tract. Surgical exploration will be the ultimate diagnostic procedure for many such patients but should be postponed until all other diagnostic methods have been employed and until there has been ample opportunity to make certain that the bleeding persists despite withdrawal of all drugs which might be causative. Because it is easier to recognize a known cause of bleeding, we have presented examples of unusual causes from our own experience.