Acute laryngitis tends to aggravate at night mainly due to postural factors, acid reflux, physiological reasons, excessive use of voice during the day and so on. 1. Postural factors: the lying position at night leads to a certain degree of compression of the respiratory tract, resulting in poor breathing and increased pain. 2. Gastric acid reflux: the vagus nerve is excited at night, which leads to the reflux of gastric acid into the throat, causing irritation to the inflamed area. 3. Physiological reasons: reduced secretion of mucus in the throat at night, as well as the possibility of open-mouth breathing during sleep, leading to a drier throat cavity, which may aggravate the symptoms. 4. Excessive use of voice during the day: a lot of vocalization during the daytime work life, resulting in the vocal cords do not get enough rest, night edema is obvious, hissing prominent. Acute laryngitis need to go to the hospital in time, under the guidance of the doctor to complete the relevant diagnosis and treatment.