A list of all the herbs and items that Mexicans use for medicinal purposes would fill hundreds of pages. Maximino Martínez's outdated, fragmentary, but still much-used Las plantas medicinales de Mexico is 659 pages long. Surely important natural cures are being forgotten every day as old traditions die away. The few medicinal herbs mentioned below can only hint at what might be found by anyone browsing among mercado herb stalls.

Page about medicinal plants from the Florentine Codex produced during the late 1500s by the Franciscan friar Bernardino de Sahagún, who documented Aztec life as described and illustrated by native Mexicans; copyright free image from the Digital Edition of the Florentine Codex created by Gary Francisco Keller and made available through Wikimedia Commons.

Many of the herbs in Mexican herb stalls have been introduced from other continents. This reminds us that more than Mexican-mercado herb stalls being museumlike vestiges of the past, they are serious "people's pharmacies" where people go for traditional cures, either because they believe in the cures, or because that's all they can afford.

When you study Mexican herbal remedies, notice how often the Doctrine of Signatures is in evidence. This is the principle that a plant indicates its use for human beings by its shape, behavior, odor, or some other natural feature. Thus an infusion of doradilla, the little resurrection plant growing on rocks and perhaps giving the impression that is breaking up the rock, is used traditionally by Mexicans to break up kidney and gall stones. Hierba de la golondrina, a euphorbia with milky-white latex oozing from any breaks inflicted on its skin, is used to cure eye diseases of the sort characterized by a milky opaqueness spreading across the lens. However, the Doctrine of Signatures often is very misleading; for example, certain euphorbia latex may cause serious damage to the eyes.

Travelers should be wary of using traditional herbs, unless the herbs are known to have a long history of medicinal use, as with epazote and its use against intestinal worms. Very often an herb that is medicinal in one dosage is poisonous in others. Some of these herbs are extremely potent!

• Aguacate: (avocado, Persea americana): for intestinal worms, grate 8 to 10 grams of fresh avocado-pit rind into a glass of water, and the next day sweeten it, drink, and eat nothing
• Altea (plantain, Plantago spp.): for dysentery, cook the root in rice
• Añil: (indigo, Indigofera suffruticosa): for children's headaches, boil leaves until soft, then apply the leaves like a bandage to the forehead
• Arnica: (golden aster, Heterotheca inuloides): for bruises, boil the flower heads into a mass, and apply
• Borraja: (borage, Borago officinalis): for bronchitis and fevers, boil 10 grams of flowers and young leaves in a liter of water, and drink the tea

Bougainvillea flower head
• Bugambilia: (bougainvillea): for clogged sinuses accompanying colds a pretty pink tea is made from Bougainvillea flowering heads such as seen at the right
• Cedrón: (lemon verbena, Aloysia triphylla): tea from the boiled leaves, taken while fasting, regularizes the menstrual flow, and expels worms
• Chicalote: (prickly poppy, Argemone ochroleuca): for stomach pain, mash 4 grams of seeds in 200 cc of water, take two or three times a day
• Clavellina: (ceiba, Bombax palmeri): for skin wounds, roast and grind the bark, and apply
• Codo de fraile: (oleander, Thevetia thevetioides): for hemorrhoids, mash seeds, mix in lard, and apply
• Cola de caballo: (horsetail, Equisetum spp.): brewed teas of the stems are diuretic, and have been used against dysentery and gonorrhea
• Culantrillo: (maidenhair fern, Adiantum capillus): to "thin the blood," for constipation, liver problems, and kidney stones, boil about 5 grams in half a liter of water, and take a small cup every day
• Damiana: (turnera, Turnera diffusa): for nervousness and weakness, take a tea made by boiling the macerated leaves
• Doradilla: (resurrection plant, Selaginella lepidophylla an infusion has salutary effects on the kidneys and liver, and breaks up gallstones.
• Encino: (oak, Quercus spp.): for diarrhea, drink tea made from boiling the tree's bark
• Gordolobo: (cudweed Gnaphalium spp.): a handful of this weedy herb brewed in a pot of water is very much used against coughs and sore throats.
• Guamúchil: (Manila tamarind, Pithecellobium dulce): for diarrhea, bloody and otherwise, boil bark from the root and drink
• Hierba de la golondrina: (spurge, Euphorbia spp): white latex from the plant is famed for curing "spots on the eye"
• Lantén: (plantain, Plantago spp.): for burns, bruises, and mouth sores, boil 100 grams of leaves in 500 ml of water, and wash the affected area
• Magnolia: (magnolia, Talauma mexicana): a tea from the bark serves as a general tonic, but too much causes the heart to beat irregularly
• Maguey: (maguey, Agave atrovirens): for bruises and pains resulting from hard blows to the body, squeeze juice from a roasted leaf, boil it down, sweeten, and drink
• Muicle: (jacobinia, Jacobinia spicigera): a tea from the leaves combats dysentery
• Nanche: (golden spoon, Byrsonima crassifolia): to improve digestion and appetite, and generally improve one's feeling, cook the bark and drink the tea
• Naranjo agrio: (sour orange, Citrus aurantium): a tea from the leaves is used as a general tonic, calming agent, for heart palpitations, and epilepsy
• Nogal: (walnut, Juglans regia): wash skin sores and cure thrush in infants with a tea made from boiled leaves
• Ortiga: (jatropa, Jatropha spp.): several different plants are called ortiga, but the roots of this one are used against venereal diseases
• Palo dulce: (eysenhardtia, Eysenhardtia polystachya): for kidney problems, place wood chips into water, and when the water turns blue, then red or amber, drink
• Pata de león: (wild geranium, Geranium spp.): an infusion of this herb is added to the bath water of babies to rid them of the rash; the brew is also good for washing wounds.

Pericón
• Pericón, yerbanís, Santa María and several other such neams, seen at the right: in English this native plant is known as Sweetscented Marigold, Mexican Marigold, Mexican Tarragon and other names; it's Tagetes lucida, used both to spice up meals, and for stomachache, menstrual problems, asthma and more, plus strong infusions historically were used ceremonially to summon closed-eye images and/or mild euphoria
• Pingüica: (manzanita, Arctostaphylos pungens): for kidney problems, drink a tea made from boiled leaves and fruits
• Romero: (rosemary, Rosmarinus officinalis): to improve the digestion, drink a tea made of the boiled leaves
• Ruda:, (rue, Ruta graveolens): highly regarded for its abilities to induce menstruation, and to abort fetuses; in too high concentrations, it is exceedingly poisonous.
• Sauco: (elderberry, Sambucus mexicana): for the cough, make a tea from the boiled flowers

• Su-tut (Helicteres guazumifolia), a small tree of the Yucatan scrub: fruit, shown at right, found in Mérida. Sold for children who don't speak clearly. An old man said, "You put a fruit into the child's mouth, twist it nine times in one direction, then twist it nine times in the other direction, and after you do that for a few weeks the child no longer has problems speaking."

• Tejocote: (hawthorn, Crataegus mexicana): to "flush out the kidneys," boil the root in water and drink the tea
• Tepopote: (Mormon tea, Ephedra antisyphilitica): a tea from the boiled stems is used against venereal diseases and kidney problems
• Tilia: (linden or basswood, Tilia spp.): for coughs, a tea brewed from the boiled flowers is drunk
• Uña de gato: (pisonia, Pisonia aculeata): several plants go by this name, but for this one, a member of the four o'clock family, drink tea from boiled leaves and bark to ease arthritic pain in joints
• Zacate limón: (lemon-grass, or citronella, Cymbopogon nardus): the lemony brewed tea is a good anti-flatulent and soothes the intestines in general

Braided garlic at mercado in San Cristobal de las Casas, Chiapas; copyright free image by Adam Jones made available through Wikimedia Commons.

One medicinal plant deserves special mention. Anyone seeing the number of stalls a good-size mercado devotes to AJO, or garlic, will be impressed by how important Mexicans seem to regard this bulb. Most garlic of course is destined for culinary use, but the traditional Mexican pharmacopoeia also grants garlic an eminent place.

Garlic juice is applied to scorpion stings and spider bites. Garlic taken internally is regarded by many as a stimulant to the body in general, and traditionally has been used to control hypertension and arteriosclerosis. For these latter purposes several cloves are mashed, the paste is placed in a glass, and just enough drinking alcohol is added to cover it. Every day for a week the glass's contents is stirred. Finally it is strained, and then after every meal five drops are taken. The next week the dosage is doubled, and every week this doubling is continued, until arriving at twenty drops per dosage. After a week of twenty drops, the dosage is diminished to fifteen drops for a week, and then ten and five drops on subsequent weeks. At the end of the second five-drop week, the treatment is ended.