Citronella: a summer oil that holds mosquitoes off for a while but does not replace repellent

Q: What is the difference between citronella and lemongrass?

They are two different grasses of the genus Cymbopogon. Citronella contains mainly citronellal and geraniol and is mild on the skin; lemongrass is largely citral and is diluted to at most 0.7% on the skin.

Citronella smells like a summer terrace and holds mosquitoes off for a while. Where the line lies between a fragrance oil and a repellent, how to dilute it and what to blend it with.

In brief: Citronella oil (at Pěstík, Java citronella Cymbopogon winterianus from Indonesia) is the scent of summer terraces. It contains citronellal, geraniol and citronellol, and repels mosquitoes for a short time, but it does not replace a registered repellent. In a diffuser 3–5 drops, on the skin 1–2%, that is, 6–12 drops per 30 ml.

Latin name	Cymbopogon winterianus (Java citronella); Ceylon citronella is C. nardus
Extraction	steam distillation of the leaves, Indonesia
Main components (Java type)	citronellal 32–45%, geraniol 21–24%, citronellol 11–15%
Dilution on the skin	usually 1–2% (6–12 drops per 30 ml); upper limit of Tisserand & Young 18.2%
Against insects	short-lived effect, not a registered biocide
Safety in one word	mild

Citronella is a grass that gave its name to the candles on garden tables. Its oil smells citrusy, slightly fruity and sweetish, less sharp than lemongrass. It is precisely because of the scent and the reputation "against mosquitoes" that it is one of the best-selling oils of the summer.

This article explains how citronella differs from lemongrass, what to expect from it outdoors, where the line lies between an aromatic raw material and a repellent, and how to dilute it. It is not medical advice.

Java and Ceylon citronella

Two oils are sold under the name citronella. The Java oil from Cymbopogon winterianus is more common today and smells fresher, because it has more citronellal. The Ceylon oil from C. nardus has less citronellal and more geraniol, limonene and methyl isoeugenol; the scent is woodier and more "smoky".

Component	Java (C. winterianus)	Ceylon (C. nardus)
Citronellal	32–45%	5–15%
Geraniol	21–24%	18–20%
Citronellol	11–15%	6–8%
Limonene	1–4%	9–11%
Methyl isoeugenol	not listed among the main components	7–11%

Citronella from Pěstík is of the Java type. Do not confuse it with lemongrass (C. flexuosus, C. citratus): that is largely citral and is diluted much more on the skin; see the article on lemongrass. Citronellol, one of the components of citronella, is covered in detail in the article citronellol in essential oils.

Citronella and mosquitoes: what is true

Citronella oil has been used against insects for decades and in the USA it has been registered as an active substance of repellents since 1948. Compared with DEET or icaridin, however, it acts for a short time, because it evaporates quickly, and it has to be renewed often. According to comparative tests, citronella candles do not work against mosquitoes of the Aedes type.

An essential oil from a bottle is not a repellent in the legal sense. In the EU, a product that promises protection against insects must be approved as a biocide with a verified dose and duration of effect. The US CDC recommends registered repellents and, for unregistered natural products, states that their effectiveness is not known.

In practice this means:

On a terrace, balcony and when grilling, citronella in an oil burner or diffuser smells pleasant and may deter some insects. But count on the mosquitoes arriving anyway.
For a trip into nature where ticks are a threat (tick-borne encephalitis, Lyme disease), and for travel to areas with dengue or malaria, use a registered repellent with DEET, icaridin, IR3535 or PMD. Citronella oil cannot bear that reliance.

More about research on oils against mosquitoes can be found in the article what science reveals about essential oils against mosquitoes, and herbs for the garden in the article how to deal with mosquitoes using herbs.

How to use citronella

Diffuser and oil burner

For a small room 2–3 drops, for a living room 3–5 drops. Outdoors on a table, a ceramic oil burner with 4–6 drops is more practical, because the air quickly blows the scent away. More on dosing in the article how many drops for a diffuser and oil burner.

On the skin

Tisserand and Young give a high upper limit of 18.2% for citronella, but that is a toxicological ceiling, not a recommended dose. For ordinary use on the body 1–2% is enough, for sensitive skin 0.5–1%:

Carrier oil	1%	2%
10 ml	2 drops	4 drops
30 ml	6 drops	12 drops
50 ml	10 drops	20 drops

We count 1 ml ≈ 20 drops. Geraniol and citronellol are among the substances that the EU lists in cosmetics as possible allergens, so always test a new oil on the forearm and wait 24 hours.

Bath

Never drip oil straight into the water. Mix 3–5 drops into a spoonful of carrier oil or cream and only then pour it into the bath.

Blends with citronella

Summer evening on the terrace (oil burner)

3 drops of citronella, 2 drops of lavender, 1 drop of grapefruit. We recommend the same combination on the product page of the oil.

Green garden (diffuser)

3 drops of citronella, 1 drop of rosemary, 1 drop of peppermint. A herbal, sharper blend. Because of the rosemary and mint, not in the room of children under 6.

Floral (diffuser)

2 drops of citronella, 2 drops of geranium. Geranium shares geraniol and citronellol with citronella, and the scents suit each other.

Body oil for an evening outdoors (1.5%)

Pour 30 ml of jojoba oil.
Add 5 drops of citronella, 3 drops of lavender and 1 drop of geranium, 9 drops in total.
Mix and label with the date.
Test on the forearm and wait 24 hours.
Use on the arms and legs as a fragrance oil, not as protection against ticks. Use within 3 months.

Spray for fabric and for a space

100 ml of distilled water, 10 ml of alcohol (helps the oil disperse) and 15 drops of citronella. Shake before each use and spray on a tablecloth, cushions on the terrace or into the air, not on the skin or in the face. On silk and light fabrics, test first in a hidden spot.

Traditional use

Citronella is traditionally used in the perfumery of soaps and cleaning products and as a raw material for the production of citronellal and geraniol. In home aromatherapy it is mainly a summer scent for a space. The essential oil is not taken internally.

What to watch out for

Children: in a diffuser in a child's room at most 1–2 drops and only when the child can leave; on children's skin better only from 6 years and at most 1%. For small children outdoors, long-sleeved clothing and netting are safer. The rules in detail are in the article essential oils and children.
Pregnancy: citronella is not among the forbidden oils, but on the skin keep it to 1%.
Medicines: for citronella, Tisserand and Young point to possible interactions with medicines. If you take medicines regularly, consult a doctor.
Animals: citronella collars and sprays for dogs are separate products, not a home blend. Do not apply the oil to cats' fur, and run a diffuser only where they can leave. More in the article essential oils and pets.
Eyes and mucous membranes: do not spray the spray into the face; if it gets in the eye, rinse with water.

How to recognise a good citronella

On the label look for the species (C. winterianus or C. nardus), because they differ in scent and composition. Also the country of origin (Indonesia, Sri Lanka, China, India) and steam distillation of the leaves. The oil is pale to dark yellow. Beware of cheap "citronella oil" in candles and scented lamps: it is often a fragrance blend, not an essential oil.

Frequently asked questions

Does citronella work against mosquitoes?

Briefly yes, but the oil evaporates quickly and the effect has to be renewed. An essential oil is not a registered repellent; in areas with ticks or tropical diseases, use a product with DEET, icaridin or PMD.

What is the difference between citronella and lemongrass?

They are two different grasses of the genus Cymbopogon. Citronella contains mainly citronellal and geraniol and is mild on the skin; lemongrass is largely citral and is diluted to at most 0.7% on the skin.

How many drops of citronella for a diffuser?

For a small room 2–3 drops, for a living room 3–5 drops. Outdoors in an oil burner 4–6 drops.

Can I apply citronella oil directly to the skin?

Not undiluted. Mix it with a carrier oil to 1–2%, that is, 6–12 drops per 30 ml, and test first on a small area.

Do citronella candles help?

Mainly they smell nice. Comparative tests show that citronella candles practically do not work against mosquitoes of the Aedes type.

Sources

Updated: 27 September 2026

Author: Jana Vránová, the editorial pen name of the Pěstík.cz team. She writes about the garden, herbs and essential oils. We take safety and dosage information from specialist literature and official sources, which we cite in every article.