BACKGROUND: Research-based standards do not exist for the management of gastric residual volumes from feeding tubes. Withdrawing and returning residual volumes can lead to clogged tubes and exposes patients to possible contamination of the feeding system. However, discarding residual volumes may place patients at risk for electrolyte imbalance and may alter fluid or nutritional balance. OBJECTIVES: To investigate the effects of discarding versus returning gastric residual volumes on body weight, serum electrolyte levels, and the rate of complications associated with tube feeding. METHODS: Thirty-five subjects receiving enteral feedings were recruited from intensive care units at 3 Midwest hospitals and randomized to a discard group or a return group. Eighteen sets of usable data were obtained. RESULTS: Repeated-measures analysis of variance indicated no significant differences between the 2 groups for any of the variables. Complications related to enteral feedings were more common in the return group (n = 8), which had 2 episodes of tube clogging and 1 episode of diarrhea and nausea. None of these complications were experienced by patients in the discard group (n = 10). CONCLUSIONS: Both groups had significant numbers of complications, including a total of 15 episodes, 7 in the discard group and 8 in the return group, of feeding delays due to high gastric residual volumes. Although serum electrolyte levels did not differ significantly between the 2 groups, potassium levels tended to be lower in the discard group. Considerations for the care of critically ill patients with feeding tubes are discussed in light of these findings.