An objective of the present invention is to provide lymphatically-transported self-emulsifying formulations for enhancing membrane permeability of poorly membrane-permeable compounds in oral administration of the compounds. It was discovered that by applying lymphatically-transported self-emulsifying formulations containing a surfactant containing oleic acid as a moiety or oily component to poorly membrane-permeable compounds containing a cyclic peptide and having features (i) and (ii) below, the membrane permeability and absorbability of the compounds can be improved: (i) log D (pH 7.4) value of the compounds is 3.2 or greater； and (ii) Caco-2 Papp (cm/sec) value of the compounds is 1.8E-6 or less.
