A double blind controlled trial of acute therapy for hemodialysis-related muscle cramps was undertaken. Cramps were graded by the subjects as moderate or severe. Fifty milliliter doses of one of three solutions were given intravenously in random fashion to 20 patients suffering a total of 100 episodes of muscle cramps. The solutions used were: (1) 7.05% NaCl (osmotic activity equivalent to 15 ml of 23.5% NaCl); (2) 50% dextrose; and (3) 5% dextrose. Relief after 3 min was reported by the subjects as complete, partial, or none. Osmotically similar concentrations of dextrose and NaCl were shown to be equally effective in providing relief of hemodialysis-related muscle cramps; both were superior to 5% dextrose.