Scientists in the United States have proven that eating carrots or dark green vegetables containing carotenoids such as spinach, rape, chard, forage, leek, mangetout, cabbage, celery leaves, lotus leaves, white potato leaves, and some yellow and red vegetables and fruits such as sweet potatoes, pumpkins, turnips, apricots, yellow peaches, mangoes, etc. can reduce the chance of cancer in smokers. Further research results reveal that eating large amounts of foods containing carotenoids can also reduce the incidence of stomach, intestinal, nasopharyngeal and skin cancers. A relative of Xu’s, an old lady, had a tumor in her abdomen and when she went to the hospital, the doctor mobilized her for removal surgery. The patient preferred to do conservative treatment because she was already over the age of her mother. Soon moved to the western suburbs of Dongsheng commune vegetable area to live in her old home. In the autumn, she ate a lot of carrots from the new harvest and had carrots as a side dish for three meals a day. Six months later, he felt that his symptoms had improved and have not developed or worsened since then. This example shows that carotenoids are beneficial in the prevention and treatment of many tumors. One molecule of carotene can be converted into two molecules of vitamin A in the human body, but this conversion requires oil. Therefore, when cooking foods containing carotenoids, sufficient fat should be added or cooked with meat, otherwise it will be difficult for carotenoids to work. According to the research material of Japanese medical doctors, it is proved that children with roundworm disease can eat food containing carotenoids. The food containing carotene can not only drive away the adult worms in children’s bodies, but also make the eggs of roundworms in the body shrink and die so that they can be eliminated from the body.