Kelp is not only an excellent food for supplementing nutrition, but also has many medical functions. Compendium of Materia Medica records that kelp can cure scabies (goiter), and it has the effect of resolving phlegm and resolving hard mass with other edematous diseases. In recent years, scientists have found that eating kelp often has an effect on preventing and treating cancer. Because kelp is rich in iodine. When the iodine content in common food or drinking water is low, it is easy to cause simple goiter, and goiter is easy to turn into thyroid tumor. Low iodine diet can also promote hormone-related breast cancer. Therefore, regular consumption of kelp can effectively prevent the occurrence of simple goiter, thus achieving the effect of preventing cancer and improving human immunity. Laminarin contained in kelp is a special amino acid, which has the functions of lowering blood pressure and preventing hypertension and cerebral hemorrhage. Seaweed food can promote intestinal peristalsis, make the stool unobstructed and prevent rectal cancer.