Miyamashikimi (Skimmia japonica Thunb.) seeds contain the following limonoids that are found in seeds of Citrus species: deacetylnomilin, nomilin, limonin, obacunone, deacetylnomilinic acid, nomilinic acid, isoobacunoic acid; and those found in seeds of Fortunella species: retrocalamin, calamin, cyclocalamin, methyl isoobacunoate diosphenol and isoobacunoate diosphenolic acid; and those found in seeds of Citrus ichangensis: ichangensin. They also contain 17-β-D-glucopyranoside of limonin, nomilin, obacunone, deacetylnomilin, calamin, retrocalamin, cyclocalamin and ichangensin. Skimmia japonica is the only plant which contains all of these limonoids. These data reveal unusual and unexpectedly high levels of citrus-like limonoids which suggest that Skimmia japonica is taxonomically closer to Citrus than previously believed.