When a patient has a cough, it is generally not recommended to eat doughnuts because they are fried foods and may cause indigestion if too many of them are eaten. Digestive function itself decreases when you have a cough, so you are more likely to suffer from indigestion, such as abdominal pain, diarrhea, stomach discomfort, nausea, vomiting and other discomforts. When you have a cough, you can eat well-digested and nutritious foods such as lean vegetable porridge, tomato and egg noodles, egg custard, vegetable noodles, etc. When you have a cough, try to avoid fried, greasy, spicy, stimulating and cold foods, and be especially careful not to overeat. If you have a cough, you should rest and drink more water, but for the elderly, you should also be careful to drink small amounts of water, not too much at one time, so as not to cause heart failure.