Lettuce (call asparagus lettuce, Qing Sun again) in the content of carbohydrate is inferior, and inorganic salt, vitamin criterion content is richer, contain more nicotinic acid especially. Nicotinic acid is the activator of insulin, diabetic person often eats some of lettuce, the metabolization function of ameliorable candy. The microelement zinc of certain amount, iron still is contained in lettuce, especially the iron element in lettuce is absorbed very easily by human body, often edible is fresh lettuce, can be short of iron sex anaemia in order to prevent and cure. The potassium ion content in lettuce is rich, it is 27 times of sodium salt content, be helpful for adjusting the balance of the salt inside body. Lettuce contains hydroxide of a kind of balmy hydrocarbon mediumly to change fat, the carcinogen in can decomposing food inferior saltpetre amine, prevent the formation of cancer cell, wait to the liver cancer of digestion, cancer of the stomach, have certain precautionary effect, also can alleviate the reaction that cancer patient puts cure or converts cure.