Drinking coffee after eating oranges will not harm your stomach. Caffeine, tannic acid, fat and other substances contained in coffee will not react with vitamin C, fruit acids and other substances in oranges, they are basically the same acidic, so oranges can be eaten with coffee, will not hurt the stomach. But drinking alcohol can not drink coffee, otherwise it will make the brain from extreme inhibition to extreme excitement, and stimulate vasodilatation, accelerate blood circulation, greatly increase the cardiovascular burden. Indigestion of the crowd to eat oranges after drinking less milk, just after drinking milk to eat oranges, milk in the protein will first meet with the fruit acids and vitamin C in oranges and solidified into blocks, affecting digestion and absorption.