Several mechanisms are involved in the intrinsic regulation of splanchnic blood flows. Of these, myogenic, metabolic, and hormonal factors appear particularly important. The relative contributions of these elements vary with the status of the tissue. Myogenic and metabolic mechanisms prevail during stress states such as arterial pressure reduction or venous pressure elevation, thereby regulating microvascular pressures and O2 exchange. During periods of enhanced functional activity, hormonal and metabolic mechanisms appear to work in concert to assure adequate delivery of nutrients and O2 to, and removal of metabolites and absorbed elements from, the active tissue.