Yawning and tearing are generally normal. As yawning produces movements such as closing the eyes, it also touches a variety of facial nerves and the eye muscles squeeze the tear glands, while the pressure in the mouth and nasal cavity increases due to various muscle contractions, affecting the discharge of tears from the nasolacrimal ducts, so it is easy to shed tears at the same time. Also yawning, usually a sign of fatigue, can also stimulate the tear glands to secrete tears, causing tears to flow from the eyes.