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.
