Yawning and tearing are generally normal phenomena. Since yawning produces actions such as closing the eyes, and at the same time touches many facial nerves, the eye muscles squeeze the tear glands, and at the same time the pressure in the mouth and nasal cavity increases due to various muscle contractions, which affects the discharge of tears from the nasolacrimal duct, so it is easy to shed tears at the same time. Moreover, yawning is usually a sign of fatigue, which also stimulates the tear glands to secrete tears, causing tears to flow from the eyes.