Rashin lactase, wanda aka fi sani da lactose inlerance, wani yanayi ne da jiki baya iya narkar da lactose, nau'in sikari da ake samu a madara da sauran kayayyakin kiwo. Lactase wani enzyme ne da aka samar a cikin ƙananan hanji kuma yana da alhakin karya lactose zuwa mafi sauƙi na sukari wanda za a iya shiga cikin jini cikin sauƙi. , ko kuma yana samar da lactase wanda baya tasiri wajen karya lactose. Sakamakon haka, lactose ya kasance ba ya narkewa a cikin tsarin narkewa, yana haifar da alamu kamar kumburi, gas, gudawa, da ciwon ciki. Mummunan bayyanar cututtuka na iya bambanta dangane da mutum da adadin lactose da aka sha.Rashin lactase na iya zama ko dai na farko ko na sakandare. Rashin lactase na farko shine kwayoyin halitta kuma yawanci yana tasowa a lokacin samartaka ko girma. Rashin lactase na biyu na iya faruwa a sakamakon wasu yanayi da ke lalata ƙananan hanji, kamar cutar celiac ko ciwon hanji mai kumburi.