The experience of producing excessive saliva, sometimes called hypersalivation, immediately after inhaling cannabis smoke is a very common, physiologically driven reaction that many users encounter. This phenomenon is a complex biological response involving two distinct systems: an immediate protective reflex triggered by the smoke and a systemic pharmacological effect caused by the compounds within the cannabis itself. While it may seem counterintuitive, this initial surge of saliva occurs for different reasons than the later sensation of dry mouth, or “cottonmouth,” that often follows. The body’s attempt to protect itself from inhaled irritants causes the initial wetting, while the active components subsequently cause a systemic drying effect.
Physical Irritation from Smoke
The most immediate cause of excessive spitting is the physical presence of smoke, which acts as a strong irritant to the delicate mucosal linings of the mouth and throat. Cannabis smoke, like any smoke, is an aerosol containing particulate matter, heat, and various chemical byproducts of combustion. These elements are immediately recognized by the body as a threat to the respiratory and oral tissues.
When these irritants make contact with the oral cavity and upper airways, they stimulate specialized sensory nerves, specifically C-fibers, triggering a centrally mediated reflex response designed to clear the irritants from the airways. The body’s defense mechanism includes processes like coughing and a rapid increase in saliva production to literally wash the irritants away. This sudden surge of saliva is an involuntary, protective reflex response. The volume of saliva quickly produced is often more than can be comfortably swallowed, leading to the sensation of excessive spitting.
Neurological Regulation of Saliva Production
The body’s saliva production is under the control of the autonomic nervous system, specifically the parasympathetic branch, which governs “rest and digest” functions like glandular secretion. The immediate hypersalivation caused by smoke irritation is a rapid parasympathetic reflex, utilizing a cholinergic pathway to signal the salivary glands to secrete fluid.
The systemic effects of cannabis begin to influence this regulatory system as the active compounds, particularly delta-9-tetrahydrocannabinol (THC), are absorbed into the bloodstream. THC interacts with the body’s endocannabinoid system, which is involved in regulating many physiological functions, including glandular secretion. Cannabinoid receptors, such as CB1, are found on the cholinergic nerves that innervate the salivary glands. When THC binds to these receptors, it inhibits the release of acetylcholine, the neurotransmitter responsible for telling the salivary glands to produce saliva. This systemic inhibition directly opposes the initial localized reflex, leading to the enduring sensation of dryness that is the classic side effect of cannabis use.
Understanding the Dry Mouth Paradox
The question of why a person spits excessively but also experiences “cottonmouth” is often called the dry mouth paradox, where two seemingly opposite symptoms occur in sequence. The initial hypersalivation is the protective reflex to the smoke, a high-volume, watery secretion designed for immediate clearance. Once the smoking stops and the irritant is removed, this reflex subsides.
As the body absorbs the THC, the systemic pharmacological effect takes over, causing a significant reduction in the basal rate of saliva production, a condition known as xerostomia. This reduction is due to THC binding to the cannabinoid receptors in the submandibular glands, which are responsible for generating the majority of saliva. The saliva that is produced under this inhibition is often thicker and stickier, lacking the lubricating quality of normal saliva. This sticky, reduced-flow saliva can feel unpleasant and may lead to a reflexive attempt to clear the throat and mouth. The two phenomena are governed by different mechanisms and timelines, with the reflexive wetting phase giving way to the systemic drying phase.
Strategies for Mitigation
Addressing the physical and neurological causes of excessive spitting and subsequent dryness requires a multi-faceted approach focused on reducing irritation and stimulating residual saliva.
Reducing Physical Irritation
To minimize the immediate physical irritation, one of the most effective methods is to cool the smoke before it enters the mouth and throat. Using devices like water pipes with ice catchers or vaporizers instead of combustion methods can significantly reduce the heat and particulate matter, lessening the reflex response.
Managing Systemic Dryness
Managing the systemic dry mouth effect centers on hydration and mechanical stimulation. Drinking plenty of water before and during the session ensures the body has enough fluid to produce high-quality saliva, even with the inhibitory effect of THC. Avoiding other dehydrating substances like alcohol and excessive caffeine can also help maintain oral moisture.
Stimulating Saliva Flow
Sucking on sugar-free hard candy or chewing sugar-free gum can physically stimulate the salivary glands to bypass the THC-induced inhibition and increase salivary flow. For long-term comfort, using over-the-counter saliva substitutes or moisturizing mouth sprays can provide direct relief to the dry tissues. These strategies help counteract both the initial reflex and the later systemic dryness, leading to a more comfortable experience.