The feeling that your mouth is suddenly dry, sticky, and cotton-like after consuming cannabis is a widely reported experience. Medically known as xerostomia, this sensation is not a sign of sudden dehydration but a direct physiological response to compounds within the cannabis plant. This effect stems from a specific biological interference with the body’s natural mechanisms for producing saliva. Understanding the underlying science reveals why cannabis makes your mouth feel so unusual.
The Mechanism: How Cannabinoids Affect Saliva Production
The primary compound responsible for this sensation is delta-9-tetrahydrocannabinol, or THC, which interacts with the body’s endocannabinoid system (ECS). The ECS is a complex network of receptors and signaling molecules that helps regulate various bodily functions, including appetite, pain, and, notably, salivation. THC mimics the body’s natural endocannabinoids, allowing it to bind to these receptors throughout the body.
The dryness is not caused by the smoke or vapor itself, as the same effect is observed with edibles and other non-inhaled forms of consumption. The targeted action occurs when THC binds to cannabinoid receptors, specifically CB1 receptors, that are found on the nerves innervating the salivary glands. These receptors are particularly prevalent on the cholinergic nerve endings that signal the submandibular glands.
The submandibular glands produce approximately 70% of the saliva in your mouth. Normally, the parasympathetic nervous system sends signals via cholinergic nerves to stimulate saliva flow. When THC binds to the CB1 receptors on these nerves, it acts as an inhibitor, temporarily blocking the signals that tell the glands to secrete moisture. This suppression causes the sudden reduction in saliva, leading to the sensation of a dry mouth.
This is a localized effect on the salivary glands, not a systemic fluid imbalance. Drinking water provides only temporary relief because the body is not dehydrated; the glands have simply been instructed to stop producing saliva. The duration of the dry mouth sensation is tied to how long THC and its metabolites remain active and bound to the receptors.
Beyond Dryness: Other Oral Sensations
While dryness is the main complaint, many people report sensations that go beyond a lack of moisture, including changes in taste perception. This phenomenon, known as dysgeusia, suggests that the ECS may influence the brain’s processing of flavor. Shifts in how food tastes might be more related to alterations in memory and cognition than to a direct physical change in the taste buds themselves.
Cannabinoid receptors are present in areas of the brain that process sensory information, potentially altering the interpretation of taste signals. Users sometimes report an enhanced desire for sweeter, saltier, or spicier foods, a result of this altered sensory processing. This change in preference can lead to a perceived dulling of normal flavors or a heightened appeal of strong ones.
Another reported sensation is a mild tingling or slight irritation of the mouth and throat, often associated with the method of consumption, such as the heat or chemical constituents found in smoke. The reduced flow of saliva also plays a role, as saliva naturally cleanses and protects the delicate mucous membranes of the mouth. When this protective layer of moisture is diminished, the mouth becomes more vulnerable to irritation.
Managing the Sensation
Although the mechanism behind dry mouth is temporary, several steps can manage the discomfort. The most immediate action is to sip water frequently, rather than attempting to gulp large amounts. While water does not restart saliva production, it provides external moisture to coat the oral tissues. Sucking on ice chips can offer similar, localized cooling relief that helps moisten the mouth.
Stimulating the residual saliva production is another effective strategy. Chewing sugar-free gum or sucking on sugar-free hard candies mechanically encourages the salivary glands to work harder. Products with a tart or sour flavor, such as lemon drops, are particularly effective because they contain citric acid, a known secretagogue that powerfully stimulates saliva flow.
For persistent or severe cases, over-the-counter products designed to treat chronic dry mouth (xerostomia) are readily available. These include moisturizing mouth sprays, gels, and artificial saliva formulations that mimic the properties of natural saliva. The method of consumption can also influence the severity, as inhaled products generally produce a more immediate and intense effect compared to edibles.