Lettuce contains abundant nicotinic acid, niacin is insulin activator, eat beneficial to elderly patients with diabetes. The lettuce can also stimulate the stomach and intestines, gastroparesis and constipation caused by diabetes role of adjuvant therapy. Lettuce is rich in potassium content, which helps to balance the salt balance in the body. For high blood pressure, heart disease, eat promote diuresis, lower blood pressure and prevention of cardiac arrhythmias role. Lettuce contains a variety of vitamins and mineral salts, which is rich in iron content, lettuce iron under the action of organic acids and enzymes, easily absorbed by the body, it is conducive to prevention and treatment of iron deficiency anemia. Lettuce fresh and slightly bitter taste, can enhance the secretion of bile and digestive gland secretion, thereby promoting digestive functions of each activity. Eat lettuce salad appetizer point, increase appetite. Excessive or regular consumption of lettuce, lettuce lettuce because of biological or chemical agents have a stimulating effect on the optic nerve, dizziness, sleepiness toxic reactions occur, resulting in night blindness or induce other eye diseases, so should not eat. Night blindness and eye disease caused by eating more lettuce lettuce only indigestion, it will improve after a few days.