Swine (6 per group) were used to study gastrointestinal blood flow during T-2 toxin-induced shock. Low- and high-dose groups were given T-2 toxin at 0.6 or 2.4 mg/kg via the pulmonary artery; controls were given the ethanol vehicle. Radiolabeled microspheres were administered into the left atrium to assess organ blood flow predosing and at 90-min intervals for 6 hr. Gastric blood flow decreased in both T-2 groups, and at 6 hr the high-dose group's value was 17% of the predose value. In the low-dose group, the lowest gastric blood flow (30% of predose) was observed 3 hr postdosing. Small-intestinal blood flow of the control group declined to 64% of the predose value. In the high-dose group, small-intestinal blood flow at 3 hr was 174% of predose, followed by a reduction to 62% at 6 hr, coinciding with a severe decline in cardiac output. Small-intestinal blood flow of the low-dose group was 159% of predose at 1.5 hr, then declined to the control value. The high-dose group's large-intestinal blood flow increased to 177% of predose at 3 hr, then declined to 66% at 6 hr. The low-dose group's large-intestinal blood flow increased to 200% of the predose value. The severe decline in gastric blood flow is probably related to the development in swine (given high doses of T-2 toxin) of a grossly bright red gastric fundus, with histologic evidence of vascular congestion and mucosal deterioration.(ABSTRACT TRUNCATED AT 250 WORDS)