Saliva (commonly known as saliva) is the key to food digestion, helps prevent tooth decay and infection, and ensures chewing and swallowing. Without saliva, the body cannot break down and digest food properly. Saliva is also one of the best health indicators.1 Saliva can be measured to detect many diseases. Saliva maintains the balance in the body, and once an imbalance occurs in the body, saliva will have a direct reflection. The doctor can reveal a series of biological secrets about the human body by testing a half-drop of eyedropper-sized saliva. British researchers have found that the measurement of a specific protein in saliva can assess a patient’s risk of heart disease. A saliva test developed by Keio University in Japan and the University of California can detect 99% of pancreatic cancers, 95% of breast cancers and 80% of oral cancers. 2. Saliva reflects stressful emotions. Once a person is stressed, salivary glands will secrete salivary alpha-amylase into the mouth. Through the measurement of this amylase, doctors can measure the stress produced by pregnant women on the fetus. Researchers explained that the imbalance of the stress hormone cortisol in saliva makes people very sensitive to stressful events.3. Saliva is six times more effective than morphine for pain relief. The British journal “Nature” published a French study found that saliva not only contains 72 different types of bacteria, but also contains a natural painkilling substance opiorphin, the analgesic effect of this substance is six times that of morphine, which helps prevent enkephalin pain signals from reaching the brain. 4, saliva secretion around the clock. The human body saliva secretion 24 hours a day, from eating every bite of food to experience stressful events, the salivary glands will increase the amount of secretion. On average, a person secretes 2 to 4 pints of saliva (about 1137 to 2273 ml) per day.5. Less saliva is secreted when there is a lot of tension and stress. A decrease in the quantity and quality of saliva is called “dry mouth syndrome”. This usually happens when you are nervous, upset or under a lot of stress. Frequent dry mouth can make it difficult to eat, chew, swallow or even speak.6. Certain medications can cause a decrease in saliva. Thick saliva indicates that it is more difficult for the salivary glands to produce saliva. Prescription and over-the-counter medications for allergies, pain, or colds can cause dry mouth. These medications can alter changes in water flow in and out of cells and, if left untreated, can lead to tooth decay, gum disease and oral infections.7 Salivary glands can also grow stones. Salivary gland stones (also called salivary stone disease) can occur in the salivary gland ducts or glands, and more than 90% occur in the submandibular gland. In addition to feeling dry mouth, patients may also experience neck pain or difficulty swallowing. The exact mechanism of salivary gland calculi is not fully understood. It is generally believed that prolonged inflammation leads to the accumulation of minerals in the salivary glands and their calcification into stones.