You can drink milk powder 15 days after appendicitis surgery, it will not affect your body, and drinking milk powder in this period of time will not cause abnormal digestive system function. Early after appendicitis surgery, you need to control your diet for a short period of time. Clinical requirement is that after normal defecation, you can start eating fluids, especially in the first 1~2 days; after that, with the gradual recovery of gastrointestinal function, you can start to eat semi-fluids, and you can fully recover in a week or so. After 15 days, you can have a normal diet, and drinking milk powder is possible, and does not affect the physical condition, but you need to moderate the amount of milk powder, not too much milk powder, to avoid increasing the function of the gastrointestinal tract to cause gastrointestinal discomfort. But clinically some people have lactose intolerance, this kind of people try to avoid drinking milk powder, mainly after drinking milk powder will cause diarrhea, cause gastrointestinal function abnormalities, at this time need to go to the hospital.