Saliva
Saliva or spit was a watery substance located in the mouths of animals and humanoids, secreted by the salivary glands. 

In  2153, Doctor Phlox located a marsupial on a class L planet whose saliva was a natural anticoagulant. ()

Months later, upon being presented with Kessick's severed finger, Phlox commented that a saliva sample would have been sufficient to confirm that Kessick was a Xindi-Primate. ()

In the mirror universe in 2155,  found traces of reptilian saliva in 's wounds, after the ensign had been killed by Slar. ()

In 2370, Data discovered Klingon DNA in the form of saliva in Deanna Troi's wound inflicted by a de-evolved Worf. ()

In 2374, Dejaren described his contempt of organic beings' eating practices as, "Secreting saliva to force food down your esophagus into a pit of digestive acids." ()

See also 
 Spit pan
 Spittoon

External link
 
Physiology