The present invention provides a composition for improving decreased absorption in the digestive tract and a composition for promoting absorption in the digestive tract, each composition comprising cystine and/or glutamine as active ingredient(s). The compositions according to the present invention can highly improve decreased absorption in the digestive tract induced by various causes, in particular, decreased absorption in the digestive tract caused by stress or exercise, and promote absorption in the digestive tract.本發明提供含有胱胺酸及麩醯胺之至少一者作為有效成分的於消化道之吸收降低的改善用組成物，或於消化道之吸收的促進用組成物。 本發明之上述組成物，可良好地改善由各種原因所引起的於消化道之吸收的降低，特別是壓力或運動所致的於消化道之吸收的降低，又，可促進於消化道之吸收。
