The main components of protein powder are protein, whey and lecithin. Eating protein powder can not only replenish the amino acids needed by human body, but also improve malnutrition and promote body metabolism, which has certain auxiliary effects on human health. Stomach cancer is a kind of malignant tumor disease, which will consume a lot of energy of human body and also cause certain invasion to the mucous membrane of stomach wall. Proper protein supplementation during the disease can strengthen the body’s resistance to the disease, and also promote wound healing and reduce the invasion of cancer cells. In addition to eating protein powder during the period of stomach cancer disease, stomach cancer patients can also take protein supplements after surgery to promote their recovery, but some stomach cancer patients have allergic reaction to protein powder and should avoid eating protein powder.