Herb library · Herb · Eschscholzia californica
California poppy
The state flower of California, sold as a calming herb for stress and poor sleep. The EMA accepts it as a traditional herbal medicine for these uses based on long-standing use, but it has only been tested in people as one ingredient of combination products, so its own effect is unknown.
Traditional use
A member of the poppy family and the state flower of California. By 1905 American physicians reported it as a mild pain reliever and sleep aid without the dangers of opium, although it belongs to the same family as the opium poppy. Today its products are commonly used for nervousness, anxiety and sleep problems, often combined with other calming herbs. In the European Union it is registered as a traditional herbal medicine for mild symptoms of mental stress and to aid sleep, a status based on long-standing use rather than on trials.
What studies show
- Limited
Anxiety: in a 2004 trial, 264 adults with mild to moderate generalized anxiety took a tablet of hawthorn, California poppy and magnesium, or a placebo, for 3 months. Anxiety scores fell more with the combination, but the trial cannot say how much of that came from the poppy.
- Insufficient
Sleep: a 2019 pilot study of 40 people gave a combination of melatonin, vitamin B6, California poppy, passionflower and lemon balm, with no comparison group. Sleep improved, but a study like this cannot show whether any single ingredient helped.
Be careful of
Cautions
- NoteIn the anxiety trial, side effects with the combination were mostly mild or moderate digestive or psychological complaints, at a rate close to placebo (11.5% versus 9.7%).
- AmountProducts vary: a 2023 analysis of eight commercial California poppy products found the main alkaloid, californidine, ranging from 0.13 to 2.55 mg per gram, about a 20-fold difference.
- NoteIt may make you drowsy: the EMA says it may impair the ability to drive or use machines. Its monograph records no reported interactions or side effects.
- ConditionThe EMA does not recommend it for anyone under 18, for lack of data. See a clinician if symptoms last more than 2 weeks or get worse.
- PregnancySafety in pregnancy and breastfeeding has not been established, and the EMA does not recommend its use then.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“This papaveraceous plant, the adopted flower of the state of California, is reputed analgesic and soporific without the dangers attending opiates.”
“Respiration is depressed by large doses, while toxic quantities impress the spinal cord.”
Sources
- European Union herbal monograph on Eschscholzia californica Cham., herba (opens in a new tab) · EMA · read September 25, 2026
- Double-blind, randomised, placebo-controlled study of a fixed combination containing Crataegus oxyacantha and Eschscholtzia californica and magnesium in mild-to-moderate anxiety disorders (Curr Med Res Opin, 2004) (opens in a new tab) · NIH · read September 25, 2026
- A combination of melatonin, vitamin B6 and medicinal plants in the treatment of mild-to-moderate insomnia: a prospective pilot study (Complement Ther Med, 2019) (opens in a new tab) · NIH · read September 25, 2026
- Alkaloids in commercial preparations of California poppy: quantification, intestinal permeability and microbiota interactions (Biomed Pharmacother, 2023) (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.