Clinically significant medication-nutrient interactions are of concern to the nutritional support practitioner. To emphasize the possible effect of the aluminum-containing medication sucralfate on serum phosphorus levels, patients admitted to the intensive care unit of a small private hospital were monitored for a 4-week period. Sixteen patients demonstrated low serum phosphorus levels; eight (50%) of these were receiving sucralfate. Eighteen patients had no low phosphorus levels measured; five (28%) patients in this group were receiving sucralfate. The hypophosphatemia observed in these patients was probably multifactorial; respiratory alkalosis and dextrose feeding as well as sucralfate use are consistent with hypophosphatemia.