Cassia oil is an essential oil extracted from the bark, leaves, and twigs of the Cinnamomum cassia tree, a member of the laurel family. It’s the source of that familiar, warm cinnamon scent you encounter in candles, baked goods, and spiced beverages. Though closely related to “true” cinnamon (Ceylon cinnamon), cassia oil has a distinct chemical profile that makes it both more potent in flavor and higher in a compound that raises safety concerns at large doses.
Where Cassia Oil Comes From
The Cinnamomum cassia tree grows across tropical and subtropical Asia, with the primary commercial production concentrated in the Guangxi and Guangdong provinces of southern China. The tree also grows in Vietnam, Sri Lanka, India, Madagascar, and the Seychelles. Most of the “cinnamon” sold in North American grocery stores actually comes from cassia rather than Ceylon cinnamon, so if you’ve ever bought a jar of ground cinnamon, you’ve likely already encountered the cassia plant.
The oil is produced through steam distillation or hydrodistillation of the bark, though leaves at various growth stages also yield essential oil. The result is a deep amber to reddish-brown liquid with an intensely warm, sweet, spicy aroma that’s significantly stronger than Ceylon cinnamon oil.
Chemical Makeup
The dominant compound in cassia oil is cinnamaldehyde, the molecule responsible for its characteristic cinnamon smell and taste. Depending on the plant material and extraction method, cinnamaldehyde can make up anywhere from about 38% to over 85% of the oil. Studies analyzing different batches have found concentrations as low as 37.72% in leaf-derived oils and as high as 86.64% in bark oils, with most commercial cassia bark oil landing in the 60% to 75% range.
Beyond cinnamaldehyde, cassia oil contains smaller amounts of cinnamyl acetate (typically 5% to 7%), along with trace compounds like copaene, cadinene, and methoxycinnamaldehyde. These secondary compounds contribute subtle woody and floral notes that round out the scent profile. For comparison, Ceylon cinnamon oil contains roughly 50% to 63% cinnamaldehyde, which is why cassia oil has a bolder, more pungent character.
How Cassia Oil Is Used
Cassia oil shows up across several industries. In food manufacturing, it serves as a flavoring agent and holds Generally Recognized as Safe (GRAS) status with the FDA under CFR 21CFR182.20, meaning it’s approved for use in foods at appropriate levels. You’ll find it in cola-flavored drinks, baked goods, candy, and spice blends where a strong cinnamon punch is desirable.
In personal care and home products, the oil is a popular ingredient in handmade soaps, candles, bath bombs, lotions, and perfumes. Its warm spice note blends well with vanilla, clove, and orange. Some people also add diluted cassia oil to DIY household cleaners for both scent and its natural antimicrobial properties.
Antimicrobial Properties
Cassia oil has demonstrated measurable antifungal activity in laboratory settings. In one study published in Scientific Reports, cassia essential oil produced inhibition zones of 51 to 80 mm against the yeast Saccharomyces cerevisiae and 75 to 90 mm against Acremonium, a mold that commonly contaminates fruit products. The oil killed both organisms at relatively low concentrations, suggesting potential as a natural preservative in the food industry.
These antifungal effects are largely attributed to cinnamaldehyde, which disrupts the cell membranes of fungi and bacteria. While these results are promising for food preservation and surface cleaning applications, lab results don’t automatically translate to clinical use on or inside the human body. The concentrations needed to kill microbes in a petri dish may cause skin irritation when applied directly.
Cassia Oil vs. Ceylon Cinnamon Oil
The most important distinction between cassia and Ceylon cinnamon oil comes down to one compound: coumarin. Cassia contains approximately 1% coumarin, while Ceylon cinnamon contains just 0.004%, roughly 250 times less. This difference matters because coumarin, when consumed regularly in high amounts, can stress the liver.
Coumarin’s potential for liver toxicity led the U.S. FDA to ban synthetic coumarin as a food additive back in 1954. Animal studies have linked a specific metabolic byproduct of coumarin to liver damage and, in rats and mice, to tumor formation. Human adverse effects are rare and generally tied to high therapeutic doses, but the European Food Safety Authority set a precautionary daily limit of 0.1 mg per kilogram of body weight. For a 150-pound adult, that works out to about 6.8 mg of coumarin per day. A single teaspoon of ground cassia cinnamon can contain 5 to 12 mg of coumarin, so regular heavy use adds up quickly.
If you use cassia oil for flavoring or aromatherapy on an occasional basis, the coumarin content is unlikely to be a concern. But if you’re consuming cassia products daily, especially as a supplement, opting for Ceylon cinnamon products reduces your coumarin exposure dramatically.
Safety Considerations
Cassia oil is one of the “hot” essential oils, meaning it can cause a burning sensation or irritation on skin contact. It should always be heavily diluted in a carrier oil before topical use, and patch testing on a small area of skin is a reasonable precaution. Most aromatherapy guidelines recommend keeping cassia oil at 0.5% or less of a topical blend.
For people taking diabetes medication, cassia cinnamon products may lower blood sugar levels on their own. Combining them with prescription blood sugar medications could cause levels to drop too low. If you’re using cassia oil or cassia supplements alongside diabetes drugs, monitoring your blood sugar more frequently helps you catch any compounding effect early.
Pregnant and breastfeeding individuals are generally advised to avoid cassia oil beyond normal food flavoring amounts, largely because of the coumarin content and the oil’s potency. The same caution applies to young children, whose smaller body weight means they hit the coumarin threshold much faster.
Choosing and Storing Cassia Oil
When shopping for cassia oil, look for bottles labeled with the full botanical name, Cinnamomum cassia, to confirm you’re getting the right species. Reputable suppliers will also list the country of origin (Chinese cassia is the most common) and provide a GC/MS report showing the chemical breakdown, including the cinnamaldehyde percentage. A high-quality cassia bark oil typically shows cinnamaldehyde above 60%.
Store the oil in a dark glass bottle away from heat and direct light. Like most essential oils, cassia oil oxidizes over time, which dulls its aroma and can increase the risk of skin sensitization. A well-stored bottle generally remains effective for two to three years.