Lemongrass, Citronella Oil

Botanical Name: Cymbopogon citratus , lemongrass, while citronella oil is more often distilled from related species such as Cymbopogon nardus and Cymbopogon winterianus. These plants belong to the same genus, which is why they are often confused or loosely grouped together in casual use.

Common Names: Lemongrass, citronella grass, citronella oil

Plant Family: Poaceae, the grass family.

Origin & History

Lemongrass and citronella have long histories in traditional systems of herbal and household use. Lemongrass has been used in teas, washes, and aromatic preparations, while citronella oil became widely known as a strongly scented oil used in insect-repelling products and topical applications. Because these plants come from closely related Cymbopogon species, people often assume they behave the same way in the body. That assumption can be a problem. Similar fragrance does not always mean similar safety, especially once the oil is concentrated and inhaled.

Qualities & Traditional Use

These plants are generally described as aromatic, sharp, penetrating, and strongly volatile. Traditionally, lemongrass has been used for its fresh scent and as a supportive herb in digestive, febrile, and general wellness practices. Citronella oil, on the other hand, is more commonly associated with environmental use, especially as a repellent. The issue begins when a concentrated essential oil is treated like a harmless plant steam. A tea made from an herb and a volatile essential oil made from that herb are not the same thing. Essential oils are chemically concentrated, and that concentration changes the risk profile.

Toxic Components & Mechanism

Lemongrass and citronella oils contain volatile compounds such as citral, citronellal, citronellol, geraniol, and related terpenes, depending on the exact species and oil composition. These compounds are highly concentrated in essential oil form. When an oil is inhaled improperly, especially through forceful steam inhalation, direct sniffing, aerosol overexposure, or accidental aspiration, oily droplets and irritating volatile compounds may reach the lower respiratory tract. Once that happens, the lungs can respond with inflammation, irritation, and chemical injury. In simple terms, the problem is not just the smell. The problem is that concentrated oil does not belong inside the delicate gas-exchange spaces of the lungs. Poison control guidance warns that aspirating essential oils can cause pneumonia, and published case literature has documented pulmonary injury after citronella oil aspiration.

Risks, Dangers & Side Effects

The main concern with citronella-type oil exposure is respiratory injury when the oil is inhaled too aggressively or enters the lungs the wrong way. This can lead to coughing, throat and airway irritation, chest discomfort, shortness of breath, and inflammatory lung reactions. In more serious situations, aspiration of essential oil can trigger chemical pneumonitis, which is a form of lung inflammation caused by irritating substances rather than infection. That is why it is more medically sound to say the oil can injure the alveoli and surrounding lung tissue than to casually describe it as a harmless inhaled botanical. Even when severe aspiration does not occur, concentrated essential oils may still irritate the respiratory tract, particularly in sensitive individuals.

Contraindications & Who Should Avoid It

This oil should be approached carefully by anyone with asthma, chronic lung irritation, COPD, reactive airways, fragrance sensitivity, or a history of respiratory allergies. Infants, young children, older adults, and pets may be more vulnerable to concentrated airborne oils. People should also avoid using concentrated lemongrass or citronella oils in a way that increases the risk of aspiration, such as putting oil too close to the nose, using excessive amounts in steam, or using preparations that can be accidentally inhaled into the lungs. The American Lung Association notes that inhaled essential oils can irritate the respiratory tract, and that people with respiratory disease may be especially susceptible.

Best Practices / Precautions

Lemongrass and citronella oils should never be treated as harmless just because they smell clean or natural. They should not be directly inhaled in a forceful or prolonged way, and they should not be used casually in heavy steam applications without understanding the respiratory risk. Diffused exposure should be moderate, intermittent, and avoided in poorly ventilated spaces. It is also important to know exactly which Cymbopogon species is being used, because product labeling can be sloppy and consumers often confuse lemongrass with citronella. Good sourcing, proper dilution, and respect for the delivery method matter just as much as the herb itself.

Summary

Lemongrass and citronella may sound gentle because they come from familiar grasses, but concentrated oil tells a different story. Once inhaled improperly or aspirated, that oil can irritate and inflame delicate lung tissue, including the alveoli, and may contribute to chemical pneumonitis. The takeaway is simple: fresh-smelling does not mean harmless, and natural does not mean safe.

References

• National Capital Poison Center. Essential oils: Poisonous when misused.

• Boots, R. J., & Weedon, Z. J. Fire-eater’s lung, including a reported case of citronella oil aspiration.

• American Lung Association. Essential oils: More harmful than helpful?

• Temple, W. A. Management of oil of citronella poisoning. PubMed.

• Dangol, S., et al. Essential Oil Composition Analysis of Cymbopogon Species.

• Kusuma, I. Y., et al. Exploring the Clinical Applications of Lemongrass Essential Oil.

• Tisserand Institute. Safety Guidelines for Essential Oil Inhalation.