The mast cells and eosinophils washed out from rat peritoneal cavity after 75 minutes of untreated hemorrhagic shock were studied in light and electron microscope. A significantly increased total peritoneal cell (PC) number, an increased mast cell (MC) number, decreased eosinophil number, and features of activation of both MC and E were found: heterogeneity and combining of granules, evacuation of their content, build up and enlargement of endoplasmic reticulum, development of microtubular cytoplasmic system, multiplication of cell membrane microvilli, and contacts between MC and E. Ultrastructural examination revealed vesicle formation in Golgie apparatus. These vesicles created characteristic blebs on the cell surface and evacuated their contents outside. Morphological findings suggest that peritoneal mast cells and eosinophils are involved in mechanism of the intestinal injury in shock.