Calea zacatechichi

The Chontal of Oaxaca call the leaves thle pela kano, “leaves of God”. Healers use the plant to clarify the senses and to receive divinatory messages in dreams, and keep this use separate from its ordinary medical use ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

A pinch of crumbled dried leaves is infused in hot water and the tea sipped slowly. The person then lies down in a quiet, secluded place and smokes a cigarette of the dried leaves. A feeling of well-being is said to last a day or more ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

Another account gives a handful of dried leaves as the dose, enough to bring serenity, nausea, drowsiness and a slower pulse. Leaves may also be placed under the pillow before sleep ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

A 16th-century account by Francisco Hernández describes a plant called ahuapatli, probably this species, used to increase appetite and treat periodic fevers. A 1615 text names a bitter herb, çacachichic, with the same description ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

In the 19th century it was described as a tonic and fever remedy. A tincture was listed in 1893 as an appetite stimulant for anorexia and liver complaints, and preparations were included as appetite and digestive agents in the Mexican Pharmacopoeia. Tests at Mexico’s Instituto Médico Nacional between 1886 and 1895 reported it effective for appetite, fever, diarrhoea and stomach ache ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

In Tepoztlán, Morelos, where it is called prodigiosa, a decoction with sugar and egg is taken for poor digestion, bile problems and wind ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

Twentieth-century sources add skin diseases, anger and tantrums (coraje and muina), respiratory and gynaecological complaints, diabetes and obesity. It was also given to rams for stomach ache ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}. Folk medicine uses it for cough and asthma as well ^{8,9Reference 8Sałaga et al. · 2015AnimalCalea zacatechichi dichloromethane extract exhibits antidiarrheal and antinociceptive effects in mouse models mimicking irritable bowel syndrome — animal in vivo studyView study →Reference 9Sałaga et al. · 2016AnimalNeuropharmacological characterization of the oneirogenic Mexican plant Calea zacatechichi aqueous extract in mice — animal in vivo studyView study →}. It is taken mainly as an infusion of the aerial parts ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

Mayagoitia and colleagues gave healthy volunteers low doses of organic extracts of the plant in a double-blind design against placebo. The extracts lengthened reaction time and changed time estimation ^{1Reference 1Mayagoitia et al. · 1986RCTPsychopharmacologic analysis of an alleged oneirogenic plant: Calea zacatechichi — double-blind, placebo-controlled human nap studyView study →}.

In a controlled nap study in the same volunteers, the extracts increased the light stages of sleep and the number of spontaneous awakenings. Reports of dreams were significantly higher than with either placebo or diazepam ^{1Reference 1Mayagoitia et al. · 1986RCTPsychopharmacologic analysis of an alleged oneirogenic plant: Calea zacatechichi — double-blind, placebo-controlled human nap studyView study →}.

In cats, the extracts produced drowsiness and EEG signs of light sleep. Their effect on brain activity differed from that of hallucinogenic and dissociative drugs such as ketamine and phencyclidine ^{1Reference 1Mayagoitia et al. · 1986RCTPsychopharmacologic analysis of an alleged oneirogenic plant: Calea zacatechichi — double-blind, placebo-controlled human nap studyView study →}.

In rats, an aqueous extract at 100 mg/kg had a mild sedative effect, increased slow-wave sleep episodes, and increased fast (gamma-band, 31–50 Hz) hippocampal activity during REM sleep ^{5Reference 5Martínez-Mota et al. · 2021AnimalCalea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects and increases hippocampal activity during REM sleep — rodent (animal) studyView study →}.

A 2025 cell and enzyme study found the aqueous extract inhibits acetylcholinesterase and tyrosinase, which may link the plant to the cholinergic and dopaminergic systems ^{15Reference 15García et al. · 2025In vitroMexican calea (Calea zacatechichi Schltdl.) interferes with cholinergic and dopaminergic pathways and causes neuroglial toxicity — in vitro studyView study →}.

Gap: the human evidence is a single small study from 1986, never replicated in people, with the extract type and dose poorly specified; the active compounds are unknown.

In healthy rabbits, a decoction of the plant significantly reduced blood sugar after a dextrose load. It was one of eight of twelve Mexican “antidiabetic” plants to do so ^{6Reference 6Román Ramos et al. · 1992AnimalHypoglycemic effect of plants used in Mexico as antidiabetics — rabbit (animal in vivo) studyView study →}.

Three major compounds of the infusion lowered blood sugar after a sucrose load in normal and diabetic (nicotinamide/streptozotocin) mice, at 3.16–31.6 mg/kg by mouth. They were the chromene demethylisoencecalin and the sesquiterpene lactones calein A and calein C. The effect was comparable to acarbose. The essential oil, at 31.6–316.2 mg/kg, also lowered blood sugar ^{7Reference 7Escandón-Rivera et al. · 2017AnimalAnti-hyperglycemic activity of major compounds from Calea ternifolia — mouse (animal in vivo) studyView study →}.

The active compounds came from the infusion, the form in which the plant is traditionally taken ^{7Reference 7Escandón-Rivera et al. · 2017AnimalAnti-hyperglycemic activity of major compounds from Calea ternifolia — mouse (animal in vivo) studyView study →}.

Gap: no human trial has tested the effect on blood sugar. The kidney-toxicity findings in rats and kidney cells bear directly on diabetes, where kidney disease is a common complication ^{13,14Reference 13González-Yáñez et al. · 2019In vitroSafety of aqueous extract of Calea ternifolia used in Mexican traditional medicine — rat (animal in vivo) and in vitro toxicity studyView study →Reference 14Mossoba et al. · 2016In vitroEvaluation of “dream herb,” Calea zacatechichi, for nephrotoxicity using human kidney proximal tubule cells — in vitro studyView study →}.

A dichloromethane extract of the leaves, stems and flowers inhibited contraction of mouse colon in vitro (IC50 about 17 µg/ml) ^{8Reference 8Sałaga et al. · 2015AnimalCalea zacatechichi dichloromethane extract exhibits antidiarrheal and antinociceptive effects in mouse models mimicking irritable bowel syndrome — animal in vivo studyView study →}.

Given by mouth at 200 mg/kg, it slowed whole-gut transit in mice from 46 to 117 minutes, suppressed hypermotility, and reduced pain in mouse models of irritable bowel syndrome ^{8Reference 8Sałaga et al. · 2015AnimalCalea zacatechichi dichloromethane extract exhibits antidiarrheal and antinociceptive effects in mouse models mimicking irritable bowel syndrome — animal in vivo studyView study →}.

Gap: a single study using a dichloromethane extract at a high mouse dose — not the traditional bitter tea or smoked leaf — so the size of the effect from a real preparation is unknown.

The dichloromethane extract reduced pain behaviour in the mouse irritable-bowel models ^{8Reference 8Sałaga et al. · 2015AnimalCalea zacatechichi dichloromethane extract exhibits antidiarrheal and antinociceptive effects in mouse models mimicking irritable bowel syndrome — animal in vivo studyView study →}. An aqueous extract reduced pain in the writhing (abdominal-pain) test in mice ^{9Reference 9Sałaga et al. · 2016AnimalNeuropharmacological characterization of the oneirogenic Mexican plant Calea zacatechichi aqueous extract in mice — animal in vivo studyView study →}.

The aqueous extract had no effect on heat pain in the hot-plate test ^{2,9Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →Reference 9Sałaga et al. · 2016AnimalNeuropharmacological characterization of the oneirogenic Mexican plant Calea zacatechichi aqueous extract in mice — animal in vivo studyView study →}.

Both are mouse models of visceral or chemical pain, and there is no human data.

An ethanol leaf extract inhibited activation of the inflammatory transcription factor NF-κB at concentrations down to 25 µg/ml. It also delayed capillary reactions in the HET-CAM egg-membrane model ^{10Reference 10Bork et al. · 1997In vitroSesquiterpene lactone–containing Mexican Indian medicinal plants and pure sesquiterpene lactones as potent inhibitors of transcription factor NF-κB — in vitro studyView study →}. The plants active in that screen were rich in sesquiterpene lactones ^{10Reference 10Bork et al. · 1997In vitroSesquiterpene lactone–containing Mexican Indian medicinal plants and pure sesquiterpene lactones as potent inhibitors of transcription factor NF-κB — in vitro studyView study →}.

An aqueous extract at 10 and 100 mg/kg prevented carrageenan-induced paw swelling in rats and reduced neutrophil migration by 44% ^{2,11Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →Reference 11Venegas-Flores et al. · 2002Antiinflammatory activity of the aqueous extract of Calea zacatechichiView study →}.

A 2025 study found the aqueous extract inhibits 5-lipoxygenase (IC50 about 72.6 µg/mL) and scavenges nitric-oxide and superoxide radicals in vitro ^{15Reference 15García et al. · 2025In vitroMexican calea (Calea zacatechichi Schltdl.) interferes with cholinergic and dopaminergic pathways and causes neuroglial toxicity — in vitro studyView study →}.

These findings are in cells and in one rat model, and the active compounds have not been standardised.

One study reported anxiety- and depression-relieving effects of an aqueous extract in several mouse and rat tests, at 0.5–50 mg/kg, similar to reference drugs ^{5Reference 5Martínez-Mota et al. · 2021AnimalCalea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects and increases hippocampal activity during REM sleep — rodent (animal) studyView study →}.

Another, testing a commercially bought aqueous extract in mice at 200–800 mg/kg, found no effect on anxiety in the elevated plus-maze ^{9Reference 9Sałaga et al. · 2016AnimalNeuropharmacological characterization of the oneirogenic Mexican plant Calea zacatechichi aqueous extract in mice — animal in vivo studyView study →}. At 400 and 800 mg/kg it lengthened immobility in the forced-swim test, the opposite of an antidepressant effect ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

The two studies differed in dose and in the source of the plant, which was wild-collected in Mexico in one and bought commercially in the other ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

Gap: directly contradictory rodent results and no human data.

Six germacranolide sesquiterpene lactones isolated from the leaves and stems, including the newly described calealactones D and E, showed significant activity against Leishmania in laboratory assays ^{4Reference 4Wu et al. · 2011In vitroAntileishmanial germacranolides from Calea zacatechichi — in vitro studyView study →}. This is activity of isolated compounds in vitro, with no animal follow-up.

A screen of medicinal plants from El Salvador found that a lipophilic extract of the plant yielded active flavones. Genkwanin and apigenin 4′,7-dimethyl ether inhibited both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum in vitro (IC50 17.1–28.5 µM) ^{12Reference 12Köhler et al. · 2002In vitroIn vitro antiplasmodial investigation of medicinal plants from El SalvadorView study →}. This is a single in-vitro study of isolated compounds.

Acute effects. A handful of leaves, the traditional divination dose, brings serenity, nausea, drowsiness and a slower heartbeat and pulse ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}. Volunteers who drank the tea or smoked the leaf reported lethargy and a short sleep with vivid dreams ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}. Large doses of extract caused salivation, loss of coordination, retching and occasional vomiting in cats ^{1Reference 1Mayagoitia et al. · 1986RCTPsychopharmacologic analysis of an alleged oneirogenic plant: Calea zacatechichi — double-blind, placebo-controlled human nap studyView study →}. Nineteenth-century tests in dogs, pigeons and rabbits found diarrhoea and vomiting but no toxic effects ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

Acute toxicity in mice. Two studies of the aqueous extract, using the standard Lorke method, found no deaths at doses up to 5,000 mg/kg. At 1,000 mg/kg and above the mice had loose stools and diarrhoea, and all survived ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}.

Kidney and liver. In rats, 8.5 mg/kg of an aqueous extract reduced platelets and white cells, raised urea and the liver enzymes ALT, AST and ALP, and caused spongy changes in the kidney tubules with lymphoid infiltrate in the liver. The same extract caused red-cell death (eryptosis) in vitro ^{13Reference 13González-Yáñez et al. · 2019In vitroSafety of aqueous extract of Calea ternifolia used in Mexican traditional medicine — rat (animal in vivo) and in vitro toxicity studyView study →}. A methanol extract damaged human kidney proximal-tubule cells and raised kidney-injury markers ^{2,14Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →Reference 14Mossoba et al. · 2016In vitroEvaluation of “dream herb,” Calea zacatechichi, for nephrotoxicity using human kidney proximal tubule cells — in vitro studyView study →}. A 2025 study found an aqueous extract toxic to nerve and microglial cells in culture ^{15Reference 15García et al. · 2025In vitroMexican calea (Calea zacatechichi Schltdl.) interferes with cholinergic and dopaminergic pathways and causes neuroglial toxicity — in vitro studyView study →}.

Drug interactions. The aqueous extract inhibited CYP3A by 99% at 375 µg/mL in vitro ^{13Reference 13González-Yáñez et al. · 2019In vitroSafety of aqueous extract of Calea ternifolia used in Mexican traditional medicine — rat (animal in vivo) and in vitro toxicity studyView study →}. CYP3A4 metabolises a large share of prescription drugs, so anyone on regular medication should check with a pharmacist. This is a single laboratory result and has not been tested in people.

Blood pressure and blood sugar. The slower pulse after a large dose ^{2Reference 2Mata et al. · 2021ReviewCalea ternifolia Kunth, the Mexican “dream herb,” a concise reviewView study →}, and the blood-sugar lowering seen in animals ^{6,7Reference 6Román Ramos et al. · 1992AnimalHypoglycemic effect of plants used in Mexico as antidiabetics — rabbit (animal in vivo) studyView study →Reference 7Escandón-Rivera et al. · 2017AnimalAnti-hyperglycemic activity of major compounds from Calea ternifolia — mouse (animal in vivo) studyView study →}, are reasons for care alongside medicines for heart disease, blood pressure or diabetes.

Smoking. Smoking the leaf can irritate the throat and cause coughing, as with any smoked herb.

Legal status. The plant is unregulated in most places but has been restricted in some. Check local law before buying or growing it.