Facebook Twitter Email Print Facebook Twitter Email Expert Advice Do pummelos interact with medications like grapefruit? Answer The pummelo, also known as shaddock, is a cross between a grapefruit and an orange and therefore contains same compounds as grapefruit. Grapefruits and pummelos block an enzyme in the liver that breaks down many medications. Blocking this enzyme means there will be higher levels of circulating medicine in the body which can be dangerous. Always check with your doctor or pharmacist about drug interactions including those with food.