Lavender: Traditional Use, Constituents and Evidence

My nan kept a row of lavender along the eastern fence of her garden in the Adelaide Hills, just past the lemon verbena and before the rosemary got completely out of hand. She'd tuck sprigs into pillowcases, steep them in vinegar for cleaning, and occasionally press a bunch into my hands when I had a headache as a kid. Whether that was medicine, habit, or ritual, I genuinely couldn't tell you. Probably some of each.

That blurry line between tradition and evidence is exactly what makes lavender one of the more interesting plants to write about. It has an extraordinarily long record of use in European, North African, and Middle Eastern botanical traditions, a reasonably well-characterised chemical profile, and a growing body of clinical research , most of it limited in scale, but interesting nonetheless.

A brief history of lavender in botanical medicine

Lavender (Lavandula angustifolia, also sold under the synonym L. officinalis) has been documented in Western herbalism since at least the first century CE, when Dioscorides described a plant matching its description in De Materia Medica. Medieval European apothecaries , particularly those in southern France and England , used lavender water, oil, and dried flowers across a wide range of applications. By the 19th century, English lavender from the Surrey hills was a major commercial crop, and lavender-based preparations appeared in pharmacopoeias across Europe.

In Australian colonial-era botanical practice, European settlers brought lavender cultivation with them. It naturalised well in cooler, drier hill regions; unsurprisingly, given that the Adelaide Hills and parts of Victoria share climatic similarities with Provence. The plant's use here largely followed British herbal traditions rather than First Nations botanical knowledge, which drew on an entirely different flora.

As a phytomedicine, lavender sits in a long tradition of aromatic plant use across multiple cultures. The essential oil, the dried flower, and aqueous extracts have all been employed in different contexts with different intended applications.

Key constituents: what's actually in lavender

The chemistry of lavender is dominated by its volatile oil fraction. L. angustifolia essential oil typically contains linalool (25–45%) and linalyl acetate (25–45%) as its primary components, with smaller proportions of ocimene, terpinene-4-ol, camphor, and 1,8-cineole (also called eucalyptol). The exact ratio shifts considerably depending on cultivar, altitude, harvest timing, and distillation method, which matters more than people generally realise when interpreting research.

Linalool is the compound that gets the most scientific attention. It's a monoterpene alcohol found across many aromatic plants, and it's the same terpene that appears in significant concentrations in some cannabis cultivars, which is one of the reasons it shows up in discussions of the entourage effect in phytocannabinoid research. Linalool has been studied extensively in preclinical models for its interactions with GABA-A receptors and NMDA receptors, among other targets. The pharmacology is genuinely interesting. But preclinical is preclinical; receptor-binding data in rodent models doesn't translate directly to human outcomes, and I always get a bit wary when popular coverage skips over that step.

Eucalyptol (1,8-cineole), present in lower concentrations in lavender than in, say, rosemary or eucalyptus, is a bicyclic ether with its own studied pharmacological interactions. Ocimene contributes to the sweet, herbaceous top notes of the oil but is present in smaller quantities. Lavender also contains flavonoids including luteolin and apigenin, as well as hydroxycinnamic acid derivatives; constituents that appear across many medicinal plants and carry their own research profiles.

For non-volatile preparations (teas, tinctures, oral extracts), the picture is different: volatile terpenes are largely absent, and the polyphenol and flavonoid fractions become more prominent. This matters because most of the clinical research on oral lavender preparations uses a specific standardised extract, not a tea or raw herb, which limits how broadly its findings apply.

What the research actually shows, and where it stops

The most-studied oral lavender preparation in clinical research is a proprietary standardised essential oil extract (80 mg capsules, with a defined linalool/linalyl acetate ratio). A series of randomised controlled trials has investigated this extract in the context of anxiety-related outcomes, the largest of which is a multicentre trial published in Phytomedicine (Kasper et al., 2010 and subsequent follow-up work). These trials generally showed statistically significant reductions in Hamilton Anxiety Rating Scale scores versus placebo. The 2014 Cochrane-style review of lavender for anxiety noted methodological limitations: small sample sizes, short durations, industry funding in some trials, and limited replication by independent groups.

That last point is, honestly, a structural problem across a lot of herbal research, not unique to lavender, but worth calling out. Trials funded by the patent-holder of a standardised extract aren't worthless, but they require independent replication before strong conclusions are drawn. The mechanistic picture from preclinical work (linalool's apparent GABA-A modulation, voltage-dependent calcium channel interactions) is plausible, but plausible mechanism plus small trials is not the same as established efficacy. I'd argue some of the popular coverage overstates where the evidence sits right now.

Topical and aromatherapy applications of lavender oil have been studied for various outcomes including sleep quality and procedural anxiety, with mixed results and mostly small, heterogeneous trials. The bioavailability question for inhaled terpenes is genuinely complex; linalool is detectable in blood after inhalation, and the olfactory-limbic pathway is a biologically plausible route for central effects, but establishing dose-response relationships via inhalation in rigorous trials is methodologically hard.

I was reading a 19th-century herbal last winter, a well-thumbed copy of Maud Grieve's A Modern Herbal that I'd found at a book fair on King William Road, and it struck me how confidently it described lavender's effects compared to how carefully we have to talk about the same plant now. That's not a loss. That's what evidence-based practice looks like.

Lavender, terpenes, and the phytocannabinoid connection

Linalool deserves a specific mention here because it appears in both lavender and cannabis, and it's one of the compounds frequently discussed in the context of how terpenes might modify cannabinoid effects. The hypothesis is that linalool, alongside terpenes like beta-caryophyllene and myrcene, may contribute to the differential character of various cannabis chemotypes; part of the broader entourage effect hypothesis.

Whether lavender's linalool content is high enough to produce pharmacologically relevant effects at typical exposure levels is a separate and genuinely open question. The preclinical receptor pharmacology is real; the translation to human aromatherapy exposure is not well established.

Australian regulatory context

In Australia, lavender preparations intended for human use sit within the TGA's complementary medicine framework. Most products are listed (ARTG Listed, "L" number) rather than registered, meaning they rely on self-assessed low-risk claims under the ARTG listing pathway rather than undergoing full pre-market efficacy evaluation. Listed complementary medicines can only carry approved "traditional use" or low-level health claims from the TGA's permitted indications list; they cannot carry claims that imply treatment or prevention of a named disease or condition.

This is worth understanding as a consumer. An "L" number on a lavender product tells you the TGA has assessed its safety and manufacturing quality, Good Manufacturing Practice compliance is required; but it does not tell you the TGA has evaluated whether the product does what the label implies. Registered ("R" number) products undergo full evidence review; most lavender products are not registered.

There are no specific import restrictions on lavender or its essential oil in Australia (unlike, for instance, kava, which is subject to import permit requirements under the Customs (Prohibited Imports) Regulations 1956 for commercial quantities, reflecting different safety and regulatory considerations). Lavender products are widely available through pharmacies, health food retailers, and online.

For practitioners incorporating lavender preparations into a clinical context, the evidence base is relevant to how products are discussed with patients. The Special Access Scheme is not applicable to lavender (it applies to unapproved prescription medicines), but understanding where a product sits on the evidence spectrum, traditional use listing versus registered indication, is relevant to informed practice.

Sources

• Listed Medicines Evidence Guidelines; Therapeutic Goods Administration (TGA)
• Silexan, an Orally Administered Lavandula Oil Preparation, Is Effective in the Treatment of 'Subsyndromal' Anxiety Disorder, Kasper et al., Phytomedicine (2010), NCBI PubMed
• Lavender and the Nervous System, Koulivand et al., Evidence-Based Complementary and Alternative Medicine (2013), NCBI PMC
• Herbal Medicines; Alcohol and Drug Foundation (ADF)

, Naomi Ellison, Botanical & phytomedicine writer