After several hours with nothing to eat or drink, saliva is the principal defense against millions of microbes inhaled with each breath. Weak alkaline saliva prevents coronavirus, 1 influenza 2 virus and adenovirus particles from infecting cells. Innate immunity protects cells against common cold viruses 3 hijacking cellular metabolism.The normal acid-base balance for blood circulating in arteries is slightly alkaline. This balance is crucial for maintaining normal physiological functions and overall health.