<P> Saliva production may also be pharmacologically stimulated by so - called sialagogues . It can also be suppressed by so - called antisialagogues . </P> <P> Spitting is the act of forcibly ejecting saliva or other substances from the mouth . It is often considered rude and a social taboo in many parts of the world, including Western countries, where it is frequently forbidden by local laws (as it was thought to facilitate the spread of disease). These laws are generally not strictly enforced . In Singapore, the fine for spitting may be as high as SGD $2,000 for multiple offenses, and one can even be arrested . In some other parts of the world, expectoration is more socially acceptable (even if officially disapproved of or illegal), and spittoons are still a common appearance in some cultures . Some animals, including humans in some cases, use spitting as an automatic defensive move . Camels are well known for doing this, though most domestic camels are trained not to . </P> <P> Many birds in the swift family, Apodidae, produce a viscous saliva during nesting season to glue together materials to construct a nest . Two species of swifts in the genus Aerodramus build their nests using only their saliva, the base for bird's nest soup . </P> <P> A common belief is that saliva contained in the mouth has natural disinfectants, which leads people to believe it is beneficial to "lick their wounds". Researchers at the University of Florida at Gainesville have discovered a protein called nerve growth factor (NGF) in the saliva of mice . Wounds doused with NGF healed twice as fast as untreated and unlicked wounds; therefore, saliva can help to heal wounds in some species . NGF has not been found in human saliva; however, researchers find human saliva contains such antibacterial agents as secretory IgA, lactoferrin, lysozyme and peroxidase . It has not been shown that human licking of wounds disinfects them, but licking is likely to help clean the wound by removing larger contaminants such as dirt and may help to directly remove infective bodies by brushing them away . Therefore, licking would be a way of wiping off pathogens, useful if clean water is not available to the animal or person . </P>

Amount of saliva secreted per day in ml