A liquid diet is one in which the food is in a liquid state and it melts into liquid in the mouth. A liquid diet is easier to swallow and digest than a semi-liquid diet. Fluid diet is mainly applied to critically ill patients who are extremely debilitated and unable to chew food, such as patients with high fever, patients with oral and cheek surgery, and patients after gastrointestinal surgery and hepatobiliary surgery, and is also often used clinically for patients with acute gastroenteritis and esophageal stricture. However, fluid diets should only be applied for a short period of time as a transitional meal, because the nutrients provided by fluid diets are incomplete. Commonly used fluid diets in clinical practice include thick rice soup, lotus root powder, almond tea, cereal porridge, steamed egg custard, egg drop soup, milk, tomato juice, fresh fruit juice, fruit tea, clear meat soup, pork liver soup, clear chicken soup, etc.