ʻO ka Lactose kahi disaccharide i loaʻa i loko o nā huahana waiu mammalian, aia i hoʻokahi mole o ka glucose a me hoʻokahi mole o ka galactose. ʻO ia ka mea nui o ka lactose, ke kumu meaʻai nui no ke kanaka a me nā mea momona ʻē aʻe i ka wā kamaliʻi. He hana nui ka lactose i ke kino o ke kanaka. He kumu ia o ka ikehu.