Waking up with drool on your pillow is a common occurrence and is usually not a cause for concern. According to Dr. Mark Wolff, dean of the University of Pennsylvania School of Dental Medicine, saliva plays a crucial role in tasting, swallowing, and protecting teeth. Daily saliva production ranges from 0.5 to 1.5 liters, and drooling typically happens when saliva accumulates faster than it can be swallowed. Experts like Dr. Emily Boss from Johns Hopkins Medicine note that during sleep, individuals swallow less frequently and have less control over mouth muscles, which can lead to drooling. Mouth breathing further increases the risk, as it allows saliva to escape more easily. Additionally, sleeping positions, such as lying on one’s side or stomach, can contribute to the problem. Children are more likely to drool, particularly babies and toddlers, who are still mastering muscle control and may produce extra saliva while teething. Understanding these factors can help mitigate any embarrassment or discomfort associated with drooling during sleep.