Medications,Pharmacology: How does VapoRub stop coughing? A scientific breakdown

October 12, 2025 •

5 min read

Since its introduction, Vicks VapoRub has been a common household remedy for cold and cough symptoms. Contrary to popular belief that it clears congestion, the product's primary mechanism is acting as a topical antitussive to quiet the cough reflex. Understanding exactly how does VapoRub stop coughing reveals a sophisticated interaction with the body's sensory nerve pathways rather than a direct treatment of the underlying illness.

Quick Summary

VapoRub contains active ingredients like menthol and camphor that stimulate sensory nerves, creating a cooling sensation and providing a counter-irritant effect. These actions modulate nerve receptors in the respiratory tract to reduce the cough reflex and ease irritation, which helps soothe throat and bronchial irritation associated with the common cold.

Key Points

Sensory Nerve Stimulation: VapoRub's active ingredients, notably menthol, stimulate specific cold receptors (TRPM8) in the nose and throat, creating a cooling sensation and distracting from irritation.
Counter-Irritant Effect: Camphor and menthol act as counter-irritants, masking discomfort and helping to soothe minor aches and cough irritation through a process of counterstimulation.
Pharmacological, Not Curative: VapoRub is a topical cough suppressant that provides symptomatic relief by modulating sensory signals, rather than curing the underlying cold or illness causing the cough.
Psychological Component: The familiar aroma and routine of applying VapoRub can provide a powerful psychological placebo effect, contributing to a feeling of comfort and relief.
Not for Internal Use or Heating: VapoRub is strictly for external use; ingestion can be toxic, and heating the product can be extremely dangerous.
Age Restrictions: For safety, VapoRub should only be used on adults and children aged two years and older.

The Active Ingredients and Their Role

When you apply VapoRub to your chest and throat, the heat from your body causes the volatile essential oils to evaporate, creating medicated vapors that are inhaled. The therapeutic effect of these vapors is due to a blend of active ingredients, each playing a specific role in managing cough and congestion symptoms.

Menthol (2.6%): As the primary active ingredient, menthol is a well-known antitussive and topical analgesic. It interacts with cold receptors, specifically the transient receptor potential melastatin 8 (TRPM8) channels, located in sensory nerves in the nose and throat. By activating these receptors, menthol creates a powerful cooling sensation that can produce a subjective feeling of clearer nasal passages and soothe minor throat irritation. This sensation provides a distraction from the discomfort of a cold, effectively reducing the urge to cough.
Camphor (4.8%): A second cough suppressant and topical pain reliever, camphor mainly affects the transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) receptors. It acts as a counter-irritant, creating a warming sensation on the skin that helps to distract from the throat and bronchial irritation causing the cough. This counterstimulation is similar to rubbing a sore muscle to alleviate pain. While VapoRub is for external use only, camphor can be highly toxic if swallowed, emphasizing the importance of proper usage.
Eucalyptus Oil (1.2%): Eucalyptus oil also functions as a cough suppressant. Its aroma contributes to the soothing effect of the vapors, and research has shown that inhaling eucalyptus vapors can be beneficial for respiratory symptoms. It also modulates TRPM8 and TRPA1 receptors, adding to the overall sensory effect.

The Placebo Effect and Psychological Comfort

Beyond the pharmacological effects of its ingredients, the application of VapoRub also involves a significant psychological component. The familiar, strong scent and the ritual of being cared for, often harking back to childhood, can evoke feelings of comfort and well-being. This psychological aspect plays a role in symptom relief, as research has shown that psychological factors can have direct biological pathways that influence how we perceive illness. In a 2010 study published in Pediatrics, parents found VapoRub to be the most effective for relieving nocturnal cough, congestion, and sleep difficulty in children when compared to a petrolatum placebo and no treatment. This study highlights that while the ingredients have a real effect, the overall user experience, including the potent aroma, contributes to the feeling of relief. Some might even say the strong smell can serve as a distraction from the irritation.

Comparison of VapoRub and Oral Cough Suppressants

To understand the unique approach VapoRub takes, it's useful to compare its mechanism with that of oral cough medicines, which work systemically.


Feature	VapoRub (Topical)	Oral Cough Suppressants (Systemic)
Mechanism of Action	Vapors from active ingredients (menthol, camphor) modulate sensory nerve receptors (e.g., TRPM8) in the respiratory tract. This creates a cooling sensation and provides counter-stimulation to suppress the cough reflex.	Active compounds (e.g., dextromethorphan) travel through the bloodstream to act on the central nervous system, affecting the cough center in the brain to suppress the reflex.
Targeted Relief	Relief is localized to the chest and throat area, where vapors are inhaled and the ointment is applied. The effect is primarily sensory and symptomatic.	Acts systemically throughout the body. Can offer broader symptom relief but may also cause systemic side effects like drowsiness or dizziness.
Speed of Action	Vapors start working within minutes to provide a soothing, calming sensation and relief from coughing.	Onset of action varies but typically takes longer than the almost instantaneous sensory effect of inhaling medicated vapors.
Safety & Side Effects	Generally safe for external use in adults and children over two. Improper use (ingestion, heating, use near face) can cause serious harm, including lipoid pneumonia in rare, chronic cases.	Potential for systemic side effects like drowsiness, excitability (especially in children), and dependency with misuse. Overdose is a significant risk with oral medications.
Contraindications	Not for use in children under two, or for ingestion. Should not be used near eyes or heated.	Use with caution with other medications, especially those affecting the central nervous system. Many formulations are not recommended for young children.

Clinical Evidence and Safe Usage

Clinical studies, including one funded by the manufacturer, have supported VapoRub's efficacy in providing symptomatic relief from cold symptoms. The 2010 study in Pediatrics compared VapoRub, petrolatum, and no treatment in children with upper respiratory infections. Researchers found that VapoRub significantly improved cough severity, frequency, congestion, and sleep compared to the other groups, although some minor irritant side effects were noted. It is crucial to use VapoRub only as directed on the label to ensure its safety and effectiveness. The product should be applied in a thick layer to the chest and throat, allowing the vapors to reach the nose and mouth naturally. Clothing should be kept loose to allow the vapors to dissipate.

Do's and Don'ts for VapoRub Use

DO apply a thick layer to the chest and throat for cough suppression.
DO keep clothing loose around the throat and chest.
DO wash your hands thoroughly after applying to avoid transferring it to your eyes or mouth.
DON'T use on children under two years old.
DON'T apply in or under the nose.
DON'T ingest the product, as it can be toxic.
DON'T heat VapoRub or add it to hot water, as it is flammable and can cause splattering and burns.

Conclusion

Ultimately, the question of how does VapoRub stop coughing is best answered by understanding its unique pharmacological approach. It doesn't eliminate the underlying cause of the cough but rather relies on the combined action of its active ingredients—menthol, camphor, and eucalyptus oil—to stimulate sensory nerves. This creates a cooling sensation and provides counter-stimulation that effectively distracts the brain and suppresses the cough reflex. Coupled with the powerful aromatics and the psychological comfort it provides, VapoRub offers symptomatic relief that helps soothe throat and bronchial irritation. However, it is essential to use it safely and as directed, especially since it is not suitable for infants and can be harmful if ingested or misused.

Learn more about the science behind VapoRub's therapeutic vapors.

Frequently Asked Questions

The vapors from VapoRub contain active ingredients like menthol, camphor, and eucalyptus oil. When inhaled, these ingredients stimulate sensory receptors in the nose and throat, creating a cooling or counter-irritant sensation that distracts the brain from the cough reflex and soothes minor irritation.

No, VapoRub is not a cure for a cold or the flu. It is a topical cough suppressant designed to temporarily relieve symptoms like coughing and minor throat irritation associated with the common cold.

VapoRub should not be used on young children, especially those under two, because the ingredients can act as irritants and cause increased mucus production and airway inflammation in their smaller airways, which can lead to respiratory distress.

No, you should never apply VapoRub in or under the nose. The camphor in the ointment can be absorbed through the mucous membranes and can be toxic. Inhaling the oil base can also lead to a rare form of pneumonia over time.

VapoRub does not physically clear a stuffy nose by reducing swelling or mucus. The menthol creates a sensory illusion of clearer airways by stimulating cold receptors in the nose, making it feel like you can breathe easier, but it does not act as a true nasal decongestant.

Menthol is the key ingredient responsible for the cough-suppressing effect. It triggers specific cold-sensing nerve receptors (TRPM8) in the respiratory tract, providing a cooling and soothing sensation that helps calm the cough reflex.

No, VapoRub should never be heated or added to hot water. It is flammable and can cause serious chemical and thermal burns if it splatters or explodes. It is meant to be applied directly to the skin to allow the body's natural heat to release the vapors.