Provided are methods for collecting saliva from the oral cavity of a mammal comprising: placing a mouthpiece of a device comprising the mouthpiece in the oral cavity of a mammal, the mouthpiece comprising a chamber defined by front and rear inner walls and a base inner wall of the mouthpiece, each of the front and rear inner walls of the chamber comprising a plurality of openings, and a switch disposed in the mouthpiece; and the device further comprising a saliva collection reservoir, a fluid supply reservoir, a pump, and means for directing fluid through said device; activating the switch disposed in the mouthpiece to pump saliva from the oral cavity to the saliva collection reservoir for collection; deactivating the pumping of saliva to the saliva collection reservoir; and subsequently pumping fluid from the fluid supply reservoir to the mouthpiece for cleaning or treatment of the oral cavity.