Digestive hemorrhages of iatrogenic origin tend to increase, possibly as a consequence of better knowledgeof subject and improved techniques. Mechanics of disease varies for the different drugs which are divided, for this purpose, into anti-inflammatory, secretagogues and anti-coagulan•;. Acetyl-salicylic acid is fundamentally a local aggressor,but there are doubts as to whether this action is related with ionization of this substance in mucosa cells or whether, on the contrary, it depends on its absortion speed through gastric epitelium. Corticoids appear to act by modifying quanti and qualitative characteristics of protective mucus.Gastrointestinal alterations conditioning hemorrhageF caused by phenylbutazone are believed to have a general toxic origin acting through the· humoral path. The group of secretagogues act by provoking excessive chlorohydro-peptic secretion and causing, furthermore,vasomotor disturbances. in the gastric submucosa. Anticoagulants may cause digestive hemorrhage due to an excessive dosis or to hypersensibility to the drug, or to a prior gastro-intestinal lesion -latent or known-, by an as yet unknown mechanism (ulcerationsinduced by anti-vitamin-K drugs). Dosis and latency period vary for eaeh drug, as do precautions which should be faken whenever thistype of drug is employed in the prophylaxis of hemorrhages.

Se estudian las hemorragias digestivas de origen yatrogénico, destacándose que su frecuencia tiende aaumentar posiblemente en relación con un mayor conocimiento del tema y al empleo de mejores técnicas de estudio.El mecanismo de acción es diferente para los distintos medicamentos que se dividen, desde este punto de vista, en antiinflamatorios, secretagogos y anticoagulantes. El ac. acetil salicílico se presenta fundamentalmente como agresor local, discutiéndose si dicha acciónestá relacionada con la ionización de la sustancia en las células de la mucosa o por el contrario depende de su velocidad de absorción a través del- epitelio gástrico. Los corticoides, en cambio, actuarían modificando las características cuanti y cualitativas del mucus protector.Las alteraciones gastrointestinales que condicionan las hemorragias por fenilbutazona "se consideran que son de ori.