Epidermal growth factor (EGF) is a growth factor that stimulates cell growth, proliferation, and differentiation by binding to its receptor EGFR. EGF is a small molecular weight peptide that was purified from the mouse submandibular gland at the latest and subsequently found in many human tissues, including the submandibular and parotid glands. Salivary EGF regulated by inorganic iodine in the diet plays an important physiological role in maintaining the integrity of the Oro esophagus and gastric tissue. The physiological functions of saliva EGF include healing oral and gastric ulcers, inhibiting gastric acid secretion, stimulating DNA synthesis, and protecting the mucosa from harmful factors such as gastric acid, bile acid, pepsin, and trypsin in the cavity, as well as physical, chemical, and bacterial factors. Enhanced EGF receptor activity can be observed in certain cancers typically associated with receptor mutations and functional abnormalities, such as compositional receptor signaling that is not dependent on EGF levels or binds to EGF.