AbstractA plethysmography technique was utilized to investigate the reactions within consecutive vascular sections of the small intestine of the cat during and after a 2–3 h local arterial hypotension at approximately 55 or 30 mm Hg produced by graded arterial occlusion. The sympathetic nerves to the intestine were cut. The resistance vessels were dilated during hypotension, the dilatation being more pronounced the lower the perfusion pressure. In the early phase of hypotension this autoregulation of intestinal blood flow was probably mainly “myogenic” while it was predominantly “metabolic” in the late part of hypotension. When releasing the arterial occlusion, blood flow returned to control after a 55 mm Hg hypotension, while a marked prolonged vasodilatation was observed after the 30 mm Hg hypotension. The capillary filtration coefficient was not changed from control during a hypotension at 55 mm Hg while it was enhanced at 30 mm Hg. Mean capillary hydrostatic pressure seemed to increase in the latter half of most experiments performed at this level. An additional, transient augmentation of capillary pressure seemed to occur after the hypotension. Upon releasing the arterial clamp after a 30 mm Hg hypotension the whole cardiovascular system seemed to derange progressively to judge by a decline of arterial blood