In 50 patients requiring enteral nutritional support, a nasogastric feeding regimen with an isotonic, polymeric solution was introduced either by the slow, conventional four-day method or by a more rapid one. The incidences of symptoms associated with either introduction protocol were compared. As many as 82% of patients showed no sign of intolerance, whatever the method used. Of the remainder, four developed symptoms that might have been associated with the treatment. Only one of these patients had been subjected to the fast introduction protocol. It is concluded that undiluted isotonic lactose-free nasoenteric solutions can be safely introduced rapidly to meet energy requirements earlier.