The occasional consumption of a small amount of non-blanched lettuce leaves is generally no significant harm, long-term lettuce leaves are not blanched if the oxalic acid content is too high, long-term consumption is likely to lead to kidney stones, calcium deficiency, and so on. Lettuce leaves is a high content of oxalic acid vegetables, not blanched directly eat contains heavy astringent flavor, and oxalic acid is easy to combine with the body’s calcium, affecting the absorption of calcium, long-term, easy to appear calcium deficiency. Oxalic acid combined with calcium to become calcium oxalate, urinary stones in some of the calcium oxalate stones, long-term lettuce leaves without blanching directly to eat easy to cause urinary stones. Every 100 grams of lettuce leaves contain 12 calories, of which 2.9 grams of carbohydrates, 1.0 grams of protein, 0.2 grams of fat, 1.3 grams of dietary fiber, 23 micrograms of folic acid, potassium 305 mg. Moderate consumption can promote intestinal peristalsis, beneficial to intestinal health. And lettuce leaves are rich in potassium, is a good food source of potassium. Lettuce leaves have more oxalic acid, it is recommended to blanch and eat in moderation.