Plant Comparison
California Poppy vs Kava
A side-by-side comparison of two medicinal plants — every documented constituent, action, use, safety note and cited source, assembled automatically from the Omnia Sana database.
At a glance
California Poppy and Kava: they share 4 indicated uses (anxiety, insomnia / sleeplessness, nervous tension, …); 2 pharmacological actions in common.
Evidence face-off — shared uses
| Condition | California Poppy | Kava | Verdict |
|---|---|---|---|
| Anxiety | 5/10 | 10/10 | Stronger for Kava |
| Insomnia / sleeplessness | 2/10 | 8/10 | Stronger for Kava |
| Nervous tension | 5/10 | 8/10 | Stronger for Kava |
| Stress | 5/10 | 8/10 | Stronger for Kava |
Evidence scores (1–10) are computed from the tier of each cited source. “Comparable” means the two scores are within one point. Follow a score to its detailed sources.
Key Constituents
Lipophilic lactones concentrated in the root/rhizome; regarded as the main anxiolytic constituents, acting on GABA-A signalling and other CNS targets.
Chalcone-type constituents of the root; implicated by structure-activity analyses as the components most likely responsible for kava-associated liver injury, which is why water-based extracts of peeled noble-cultivar root are preferred.
Pharmacological Actions
Anxiolytic for anxiety and nervous tension - also supported by a double-blind RCT of a fixed California poppy + hawthorn (Crataegus) + magnesium combination in mild-to-moderate anxiety
Standardised kava extracts significantly reduce anxiety versus placebo in controlled trials (Hamilton Anxiety scale).
Traditional & Indicated Uses
Anxiolytic for anxiety and nervous tension - also supported by a double-blind RCT of a fixed California poppy + hawthorn (Crataegus) + magnesium combination in mild-to-moderate anxiety
Mild sedative / sleep support for insomnia (positive allosteric modulation of GABA-A receptors)
Anxiolytic for anxiety and nervous tension - also supported by a double-blind RCT of a fixed California poppy + hawthorn (Crataegus) + magnesium combination in mild-to-moderate anxiety
Mild analgesic (traditional use for pain)
Directly measured as a treatment target in a 156-patient observational trial of kava extract, where nervous tension and restlessness showed the largest improvements.
Safety, Cautions & Contraindications
Has sedative activity: it can add to the effects of alcohol, sedatives and sleep medicines, so avoid combining and do not use before driving.
Alcoholic (ethanol) extracts inhibit or induce several cytochrome P450 enzymes (CYP3A4, 2C9, 2C19, 2D6) and activate the pregnane X receptor, so there is a risk of herb-drug interactions; the water-based tea appears safer in this respect. Avoid in pregnancy and breastfeeding.
Rare but serious drug-induced liver injury (hepatitis, cirrhosis, liver failure) has been reported with kava; it is contraindicated in people with liver disease and should not be combined with alcohol or other medicines that can harm the liver. To reduce risk, use only water-based extracts of peeled root/rhizome from a noble cultivar, keep the dose at or below about 250 mg kavalactones per day, and use short-term only. Stop and seek care for signs of liver trouble (dark urine, jaundice, nausea, abdominal pain).
Kavalactones inhibit several cytochrome P450 enzymes (CYP1A2, 2C9, 2C19, 2D6 and 3A4), which metabolise a large share of prescription medicines. Kava may therefore raise blood levels of such drugs; check with a pharmacist or doctor before combining kava with any regular medication.
External Ids
Botanical Description
Herbaceous perennial (often grown as an annual) with delicate, finely divided, blue-green feathery foliage. Solitary, cup-shaped, four-petalled flowers in vivid orange to yellow arise on long stalks, opening in full sun and closing at night or in dull weather, followed by a long, slender, ridged seed capsule that splits explosively when ripe.[7]
Robust, shrubby perennial with thick, jointed, cane-like stems and large, heart-shaped, glossy green leaves. The plant rarely if ever flowers or sets viable seed in cultivation and is propagated entirely by stem cuttings; the thick, knotty underground rhizome and root, the medicinal part, contains the characteristic kavalactone-rich resin.
Habitat
Native to open grassland, coastal scrub and disturbed ground of California and neighbouring states; widely cultivated and naturalised elsewhere as a garden ornamental.[7]
Native to the islands of the South Pacific (Vanuatu, Fiji, Tonga, Samoa and neighbouring islands); cultivated in warm, humid, shaded tropical conditions.
Harvesting
The flowering aerial parts are cut in summer while in flower, and dried in a warm, shaded, airy place.[7]
The root and rhizome are dug from plants at least three to five years old, when kavalactone content is highest, then cleaned, peeled and dried or processed fresh into a beverage.
Traditional Uses
California poppy has a Native American traditional reputation as a mild calming and pain-relieving remedy, used for insomnia, nervous tension and mild pain; unlike the related opium poppy it is non-addictive and its calming effects are now attributed to GABA-A receptor modulation, supporting its traditional anxiolytic and sedative use.[7]
Kava root has a centuries-long ceremonial and social tradition across Pacific Island cultures, prepared as a communal beverage for its calming, sociable and relaxing effects; this traditional anxiolytic reputation is now supported by clinical trials of standardised water-based extracts for anxiety.[6]
Preparations
Dried flowering herb infused in hot water as a traditional calming, sleep-supporting tea.
Alcoholic extract of the dried flowering herb; note that alcoholic extracts (unlike the water-based tea) can affect drug-metabolising liver enzymes.
Concentrated extract, sometimes combined with hawthorn and magnesium, studied in a clinical trial for mild-to-moderate anxiety.
Peeled root pounded or ground and mixed with water, strained and drunk fresh, the traditional Pacific Island ceremonial and social preparation.
Water-based extract standardised to kavalactone content, taken as capsules; the form used in most clinical anxiety trials, and the safer choice given documented hepatotoxicity concerns with some solvent-extracted products.
Dosage
The EU herbal monograph gives a single dose of 480-600 mg of the powdered herb and a daily dose of 960-1500 mg, in adults and elderly; for sleep, one single dose with dinner and another 30-60 minutes before bedtime. Not recommended under 18 years; consult a practitioner if symptoms persist beyond 2 weeks. Educational reference only, not a prescription.
Health Canada's NNHPD monograph gives 0.2-3 g of dried flowering herb top per day for adults 18 years and older, with infusion among the accepted methods of preparation. The EU herbal monograph covers the powdered herbal substance only and gives no infusion posology. Educational reference only, not a prescription.
Clinical trials for anxiety commonly use extracts providing up to around 250 mg kavalactones daily, from water-based extracts of peeled root of a noble cultivar, for short-term use only, given the rare but serious hepatotoxicity risk. Educational reference only, not a prescription.
References
Drug Class Interactions
Lookalikes Review
Synonyms
Not documented
Pairings
Not documented
Kava and valerian are both calming, sedating herbs; taken together they may add up to cause excessive drowsiness, so use caution and avoid before driving or combining with other sedatives.[1]
Kava and passionflower are both relaxing, sedating herbs; combined use may deepen drowsiness and sedation, so use caution.[1]
References & Sources
- Rolland, A., Fleurentin, J., Lanhers, M.C., Younos, C. et al (1991) 'Behavioural effects of the American traditional plant Eschscholzia californica: sedative and anxiolytic properties', Planta Medica, 57(3), pp. 212-216. doi:10.1055/s-2006-960076 Preclinical
https://doi.org/10.1055/s-2006-960076 - Rolland, A., Fleurentin, J., Lanhers, M.C., Misslin, R. and Mortier, F (2001) 'Neurophysiological effects of an extract of Eschscholzia californica Cham. (Papaveraceae)', Phytotherapy Research, 15(5), pp. 377-381. doi:10.1002/ptr.884 Preclinical
https://doi.org/10.1002/ptr.884 - Kalyniukova, A., Ahmed, S., Ak, G., Saka, E. et al (2025) 'Comprehensive Metabolomic Profiling and Biological Activity Analysis of Eschscholzia californica Extracts Using LC-ESI-QTOF-MS', Food Science & Nutrition, 13(9), pp. e70885. doi:10.1002/fsn3.70885 Preclinical
https://doi.org/10.1002/fsn3.70885 - Gafner, S., Dietz, B.M., McPhail, K.L., Scott, I.M., Glinski, J.A., Russell, F.E., McCollom, M.M., Budzinski, J.W., Foster, B.C., Bergeron, C., Rhyu, M.R. and Bolton, J.L (2006) 'Alkaloids from Eschscholzia californica and their capacity to inhibit binding of [3H]8-hydroxy-2-(di-N-propylamino)tetralin to 5-HT1A receptors in vitro', Journal of Natural Products, 69(3), pp. 432-435. doi:10.1021/np058114h Preclinical
https://doi.org/10.1021/np058114h - Cahlikova, L., Macakova, K., Kunes, J., Kurfurst, M., Opletal, L., Cvacka, J., Chlebek, J. and Blunden, G (2010) 'Acetylcholinesterase and butyrylcholinesterase inhibitory compounds from Eschscholzia californica (Papaveraceae)', Natural Product Communications, 5(7), pp. 1035-1038. doi:10.1177/1934578x1000500710 Preclinical
https://doi.org/10.1177/1934578x1000500710 - Singh, S., Jain, L., Pandey, M.B., Singh, U.P. and Pandey, V.B (2009) 'Antifungal activity of the alkaloids from Eschscholzia californica', Folia Microbiologica, 54(3), pp. 204-206. doi:10.1007/s12223-009-0032-7 Preclinical
https://doi.org/10.1007/s12223-009-0032-7 - Fedurco, M., Gregorova, J., Sebrlova, K., Kantorova, J., Pes, O., Baur, R., Sigel, E. and Taborska, E (2015) 'Modulatory Effects of Eschscholzia californica Alkaloids on Recombinant GABAA Receptors', Biochemistry Research International. doi:10.1155/2015/617620 Preclinical
https://doi.org/10.1155/2015/617620 - Cahlikova, L., Kucera, R., Hostalkova, A., Klimes, J. and Opletal, L (2012) 'Identification of pavinane alkaloids in the genera Argemone and Eschscholzia by GC-MS', Natural Product Communications, 7(10), pp. 1279-1281. doi:10.1177/1934578x1200701008 Preclinical
https://doi.org/10.1177/1934578x1200701008 - Manda, V.K., Ibrahim, M.A., Dale, O.R., Kumarihamy, M., Cutler, S.J., Khan, I.A., Walker, L.A., Muhammad, I. and Khan, S.I (2016) 'Modulation of CYPs, P-gp, and PXR by Eschscholzia californica (California Poppy) and Its Alkaloids', Planta Medica. doi:10.1055/s-0042-103689 Traditional / reference
https://doi.org/10.1055/s-0042-103689 - Hanus, M., Lafon, J. and Mathieu, M (2004) 'Double-blind, randomised, placebo-controlled study to evaluate the efficacy and safety of a fixed combination containing two plant extracts (Crataegus oxyacantha and Eschscholtzia californica) and magnesium in mild-to-moderate anxiety disorders', Current Medical Research and Opinion, 20(1), pp. 63--71. doi:10.1185/030079903125002603 Randomized trial
https://doi.org/10.1185/030079903125002603 - European Medicines Agency (HMPC) (2015) 'European Union herbal monograph on Eschscholzia californica Cham., herba'. Available at: https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-eschscholzia-californica-cham-herba_en.pdf Traditional / reference
https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-eschscholzia-californica-cham-herba_en.pdf - Health Canada, Natural and Non-prescription Health Products Directorate (2026) 'Natural Health Product Monograph: California Poppy - Eschscholzia californica'. Available at: https://webprod.hc-sc.gc.ca/nhpid-bdipsn/dbImages/mono_california-poppy_english.pdf Traditional / reference
https://webprod.hc-sc.gc.ca/nhpid-bdipsn/dbImages/mono_california-poppy_english.pdf - Ghasemzadeh Rahbardar, M. and Hosseinzadeh, H (2024) 'Therapeutic potential of hypnotic herbal medicines: A comprehensive review', Phytotherapy Research, 38(6), pp. 3037-3059. doi:10.1002/ptr.8201 Meta-analysis / review
https://doi.org/10.1002/ptr.8201 - Block, K.I., Gyllenhaal, C. and Mead, M.N (2004) 'Safety and efficacy of herbal sedatives in cancer care', Integrative Cancer Therapies, 3(2), pp. 128-148. doi:10.1177/1534735404265003 Meta-analysis / review
https://doi.org/10.1177/1534735404265003
- Block, K.I., Gyllenhaal, C. and Mead, M.N (2004) 'Safety and efficacy of herbal sedatives in cancer care', Integrative Cancer Therapies, 3(2), pp. 128-148. doi:10.1177/1534735404265003 Meta-analysis / review
https://doi.org/10.1177/1534735404265003 - Pittler, M.H. and Ernst, E (2000) 'Efficacy of kava extract for treating anxiety: systematic review and meta-analysis', Journal of Clinical Psychopharmacology, 20(1), pp. 84-89. doi:10.1097/00004714-200002000-00014 Meta-analysis / review
https://doi.org/10.1097/00004714-200002000-00014 - Smith, K. and Leiras, C (2018) 'The effectiveness and safety of Kava Kava for treating anxiety symptoms: A systematic review and analysis of randomized clinical trials', Complementary Therapies in Clinical Practice, 33, pp. 107-117. doi:10.1016/j.ctcp.2018.09.003 Meta-analysis / review
https://doi.org/10.1016/j.ctcp.2018.09.003 - Zhang, W., Yan, Y., Wu, Y., Yang, H., Zhu, P., Yan, F., Zhao, R., Tian, P., Wang, T., Fan, Q. and Su, Z (2022) 'Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysis', Pharmacological Research, 179, pp. 106204. doi:10.1016/j.phrs.2022.106204 Meta-analysis / review
https://doi.org/10.1016/j.phrs.2022.106204 - Sarris, J (2018) 'Herbal medicines in the treatment of psychiatric disorders: 10-year updated review', Phytotherapy Research, 32(7), pp. 1147-1162. doi:10.1002/ptr.6055 Meta-analysis / review
https://doi.org/10.1002/ptr.6055 - Pittler, M.H. and Ernst, E (2003) 'Kava extract for treating anxiety', Cochrane Database of Systematic Reviews, 2003(1), pp. CD003383. doi:10.1002/14651858.CD003383 Meta-analysis / review
https://doi.org/10.1002/14651858.CD003383 - Teschke, R., Qiu, S.X., Xuan, T.D. and Lebot, V (2011) 'Kava and kava hepatotoxicity: requirements for novel experimental, ethnobotanical and clinical studies based on a review of the evidence', Phytotherapy Research, 25(9), pp. 1263-1274. doi:10.1002/ptr.3464 Meta-analysis / review
https://doi.org/10.1002/ptr.3464 - Wang, Yingli and Su, Chao and Zhang, Bo and Niu, Yang and Ren, Ruru and Zhao, Xiaojun and Yang, Lingling and Zhang, Wannian and Ma, Xueqin (2021) 'Biological Activity, Hepatotoxicity, and Structure-Activity Relationship of Kavalactones and Flavokavins, the Two Main Bioactive Components in Kava (Piper methysticum)', Evidence-Based Complementary and Alternative Medicine, 2021, pp. 6851798. doi:10.1155/2021/6851798 Meta-analysis / review
https://doi.org/10.1155/2021/6851798 - Sarris, J., Kavanagh, D.J., Adams, J., Bone, K. and Byrne, G (2009) 'Kava Anxiety Depression Spectrum Study (KADSS): a mixed methods RCT using an aqueous extract of Piper methysticum', Complementary Therapies in Medicine, 17(3), pp. 176-178. doi:10.1016/j.ctim.2009.01.001 Randomized trial
https://doi.org/10.1016/j.ctim.2009.01.001 - Kuchta, Kenny and Hladikova, Marie and Thomsen, Michael and Nahrstedt, Adolf and Schmidt, Mathias (2020) 'Kava (Piper methysticum) Extract for the Treatment of Nervous Anxiety, Tension and Restlessness', Drug Research, 71(2), pp. 83-93. doi:10.1055/a-1268-7135 Clinical study
https://doi.org/10.1055/a-1268-7135 - Anke, Jennifer and Ramzan, Iqbal (2004) 'Pharmacokinetic and pharmacodynamic drug interactions with Kava (Piper methysticum Forst. f.)', Journal of Ethnopharmacology, 93(2-3), pp. 153-160. doi:10.1016/j.jep.2004.04.009 Meta-analysis / review
https://doi.org/10.1016/j.jep.2004.04.009 - Pittler, M.H. and Ernst, E (2003) 'Kava extract for treating anxiety', Cochrane Database of Systematic Reviews, 2003(1), pp. CD003383. doi:10.1002/14651858.CD003383 Meta-analysis / review
https://doi.org/10.1002/14651858.CD003383
Generated automatically from the Omnia Sana plant database and its cited sources. For educational purposes only — not medical advice. Always consult a qualified practitioner before using medicinal plants.