Biopharmaceuticals, medium- and high-molecular weight biologically active macromolecules, are not easily absorbed by the small intestine, the main organ responsible for gastrointestinal absorption, resulting in a bottleneck for oral administration type biopharmaceutical development. Now, researchers have found a new small intestine permeable peptide that can facilitate digestive tract absorption of biopharmaceutical products. The discovery should make it possible for oral administration of drugs that were previously only available by injection.