Herbs for Stress & Anxiety: What the Evidence Actually Says

Stress and anxiety are among the most common reasons people turn to herbs. Some of these plants do have real clinical evidence — but it is usually modest, and the marketing tends to run far ahead of the science. This guide weighs what the research actually shows, and is honest about where it doesn't.

Not medical advice. This article is for education only. If anxiety is persistent, interferes with your life, or comes with panic, chest pain, or thoughts of self-harm, please speak to a qualified clinician. Herbs are not appropriate for a crisis.

First, a distinction that matters

Everyday stress — work pressure, exams, a hard week — is a normal response that usually passes. A clinical anxiety disorder (such as generalised anxiety disorder) is a persistent, impairing medical condition that deserves proper assessment.

For both, the foundations come first: evidence-based therapy such as CBT, good sleep, exercise, and limiting caffeine and alcohol have the strongest support. Herbs, where they help at all, are best seen as a modest adjunct — and ideally discussed with a clinician, especially if you take other medication.

Ashwagandha (Withania somnifera)

Evidence — the strongest signal among the adaptogens, but read the fine print. Several reviews of randomised trials report reductions in self-rated stress, anxiety, and cortisol versus placebo. The caveats are real: trials are mostly small, short, and often industry-linked, so effects are probably overstated and long-term safety is not well established.

Evidence level: clinical (multiple RCTs), modest quality. How it's used: standardised root-extract capsules; powder. Safety: generally well tolerated short-term (GI upset, drowsiness). Rare reports of liver injury; can affect thyroid hormones (caution with thyroid disease or medication); may add to sedatives and affect blood-sugar/blood-pressure drugs. Avoid in pregnancy.

See our entry on Ashwagandha.

Lavender (Lavandula angustifolia)

Evidence — the best clinical evidence here, but for one specific product. A standardised oral lavender-oil preparation reduced anxiety versus placebo in a large GAD trial, with results comparable to a common prescription medicine. The crucial caveat: this applies to that standardised oral preparation — not to lavender tea or aromatherapy, where the evidence for anxiety is much weaker.

Evidence level: clinical (RCTs + meta-analyses) for the standardised oral product. How it's used: standardised oral capsules; also aromatherapy and tea (weaker evidence). Safety: mainly mild — belching, lavender breath, occasional nausea. No sedation or dependence seen in trials. Insufficient data in pregnancy — avoid as a precaution.

See Lavender.

Chamomile (Matricaria chamomilla)

Evidence — promising for anxiety, but limited. A placebo-controlled trial in mild-to-moderate GAD found a meaningful reduction in symptoms over eight weeks. A longer continuation study hinted at fewer relapses but was not statistically significant. Few trials, modest sizes — promising, not proven.

Evidence level: clinical (small RCTs), preliminary. How it's used: tea; standardised extracts. Safety: key concern is allergy in people sensitive to ragweed, daisies or marigolds (Asteraceae); possible interaction with the blood thinner warfarin. Caution in pregnancy.

See Chamomile.

Lemon balm (Melissa officinalis)

Evidence — preliminary calming effect. Small trials and one meta-analysis suggest improvements in anxiety and mood, plus acute calming under stress. Studies are small, short, and often use combination products — treat as preliminary.

Evidence level: preliminary clinical; EU traditional-use. How it's used: tea, tinctures, capsules; often combined with valerian. Safety: well tolerated; mild sedation possible. Theoretical caution with thyroid medication and other sedatives. Avoid medicinal doses in pregnancy.

See Lemon balm.

Passionflower (Passiflora incarnata)

Evidence — weak and inconclusive. Most small trials report reduced anxiety, and one found a pre-surgery calming effect, but a Cochrane review concluded the data were too sparse to draw conclusions. Largely traditional use.

Evidence level: preliminary / mostly traditional. How it's used: tea, tincture, extracts; often combined with valerian or lemon balm. Safety: can cause drowsiness; adds to sedatives and alcohol. Avoid in pregnancy. Caution before driving.

See Passionflower.

Rhodiola (Rhodiola rosea)

Evidence — weak and uncertain, and more about fatigue than anxiety. Some trials suggest benefit for stress-related fatigue and burnout, but reviewers judged the studies to be at high risk of bias with contradictory results. Direct evidence for clinical anxiety is thin.

Evidence level: preliminary, low-quality. How it's used: standardised root-extract capsules; tincture. Safety: usually well tolerated; can cause overstimulation or jitteriness (often taken earlier in the day). Possible interactions with antidepressants and blood-pressure/diabetes drugs; caution in bipolar disorder. Avoid in pregnancy.

See Rhodiola.

⚠️ A word on kava (Piper methysticum)

Kava does have clinical evidence for reducing anxiety — but it is linked to serious, occasionally fatal liver injury, and has been banned or restricted in several countries. We include it only as a caution, not a recommendation. It should never be used alongside alcohol, sedatives, or other liver-stressing drugs, and is unsuitable for anyone with liver risk factors or in pregnancy. If you are considering kava, do so only under medical supervision.

The honest bottom line

  • Therapy and lifestyle first. For a clinical anxiety disorder, herbs are not a substitute for proper care.
  • The best-supported options are the standardised oral lavender preparation and ashwagandha — and even these rest on small or modest trials.
  • Passionflower and rhodiola have weak, uncertain evidence; don't expect much.
  • "Natural" does not mean free of interactions. Ashwagandha (thyroid, liver), chamomile and passionflower (anticoagulants), and several others can interact with medicines. Anyone on prescriptions, pregnant, or breastfeeding should check with a clinician first.
  • Avoid kava unless medically supervised — the liver risk is real.

If anxiety is persistent or disabling, or comes with panic or low mood, see a clinician. Herbs shouldn't delay care that helps.

Explore the plants in our anxiety-related catalogue or the full plant catalogue. For books on herbal medicine, see our Shop.