To assess the radiosulfur colloid distribution in the liver-spleen scans of trauma patients, 73 trauma patients (age: 4-74 years, mean: 32 years) who had Tc-99m sulfur colloid liver-spleen scans for trauma workup were studied and compared with the liver-spleen scans of 87 control patients (age: 2-64 years, mean: 36 years). Radiocolloid distribution was visually assessed by two physicians independently, and the areas of the greatest density in the liver and spleen on the posterior view that included both organs were compared. The scans were grouped into three grades: Grade I, liver density greater than spleen density; Grade II, both organs showing equal density; and Grade III, splenic density greater than liver density (colloid shift). Forty-three of the trauma patients (59%) were in Grade III, 22 (30%) in Grade I, and 2 (11%) in Grade II. The control group had 12 (14%) patients in Grade III, 54 (62%) in Grade I, and 21 (24%) in Grade II. When the young adults and children of the trauma patients (age: 4-20 years, mean: 14 years) were looked at separately, 17 of 20 (85%) showed colloid shift (Grade III). It is concluded that there is a significantly higher incidence of colloid shift in trauma patients compared to control patients (P less than .01).