Rosemary is a fragrant, woody herb native to the Mediterranean region, commonly used in cooking and traditional medicine. This aromatic plant has seen a rise in popularity as people explore non-tobacco smoking alternatives, prompting questions about its safety when combusted. While rosemary is recognized for its beneficial properties, the chemical changes that occur when the dried leaves are burned introduce health considerations. Understanding the herb’s natural composition and the effects of combustion provides the necessary context to address the risks of inhaling rosemary smoke.
Chemical Components of Rosemary
The distinctive scent and therapeutic qualities of the herb come from its high content of volatile organic compounds. Two of the most prominent components are 1,8-cineole (eucalyptol) and camphor. The concentration of these compounds can vary widely depending on the plant’s chemotype, or chemical variety, and where it was grown.
In various rosemary oils, 1,8-cineole typically accounts for 16% to 38%. Camphor is also highly abundant, sometimes making up 13% to 33% of the oil’s composition. These high concentrations of powerful terpenes are safe when consumed in food quantities or used in diluted form, but they present a different hazard when subjected to high heat.
Health Implications of Inhaling Burnt Rosemary
Smoking rosemary involves inhaling the products of incomplete combustion, which are toxic. This process creates carbon monoxide and fine particulate matter (PM2.5), which can travel deep into the respiratory tract and lungs. These particles are capable of bypassing the body’s natural defense mechanisms, causing irritation and inflammation in the airways.
Inhaling any smoke introduces carcinogens, such as polycyclic aromatic hydrocarbons (PAHs), and sticky residue known as tar, which coats the lungs and impairs the function of the cilia. Studies on other plant materials have shown that the combustion of dried herbs can generate high levels of particulate matter. This general smoke exposure can lead to chronic respiratory conditions and increased risk of cardiovascular issues over time.
Specific Dangers of Rosemary Components
Beyond these generalized combustion risks, the high levels of camphor and 1,8-cineole in rosemary present specific dangers. When burned and inhaled, these concentrated monoterpenes act as severe irritants to the mucous membranes of the respiratory tract. Exposure can induce coughing, wheezing, and a burning sensation in the throat and nose. Inhaling high doses of camphor fumes is known to cause central nervous system effects. Symptoms of toxicity can include headaches, confusion, dizziness, and seizures.
Safer Methods for Using Rosemary
Individuals seeking to benefit from rosemary’s aromatic qualities or traditional uses can choose several non-combustion methods that avoid lung damage. Incorporating the fresh or dried herb into cooking allows for safe ingestion and flavor without producing toxic smoke. Making a rosemary herbal infusion, or tea, is another safe option that releases the beneficial compounds through gentle steeping in hot water.
Rosemary essential oil can be used through aromatherapy by adding a few drops to a cool-mist diffuser, which disperses the oil’s scent into the air without burning it. This method is commonly used to support cognitive function and clear congestion. For external uses, the essential oil can be diluted with a carrier oil, such as jojoba or coconut oil, and applied to the skin for muscle soreness or as a scalp massage.