Similarities between ethnomedical studies in northeastern Mexico and Mesoamérica
The length and breadth of Mexico show strong similarities regarding wild and cultivated medicinal taxa and their uses. From Veracruz the plant families Asteraceae, Piperaceae, Leguminosae and Euphorbiaceae agglutinate the most important genera and species with medicinal use . In arid and semiarid lands in the south of Puebla, 98 medicinal species were recorded , of those, 18 cultivated (Carica, Citrus, Coriandrium, Cucurbita, Ficus, Lycopersicon, Persea, Petroselinum, Phaseolus, Prunus, Psidium, Sechium, and Zea), and 4 wild species (Amaranthus, Castela, Opuntia, and Quercus) were found also to be common in our area. Furthermore, leaves are the most common parts used in the healing process; of the 46 medicinal species recorded in the Tehuacán-Cuicatlán Valley , 12 wild and 16 cultivated are also found in our study area, cooking being the most common method; cultivated medicinal plants in north of México and Mesoamérica are used as fruit trees, among those are Prunus domestica, P. persica, P. serotina, and Ficus carica; some medicinal species recorded form Zitácuaro, Michoacán  are used in similar way in southern Nuevo León such as, Chenopodium ambrosioides, Lycopersicon esculentum, Malva parviflora, Opuntia ficus-indica, Portulaca oleracea, Punica granatum, and Tagetes lucida; a large number of species and number of uses are shared between Ocotlán, Oaxaca and our study area, 83 genera and 32 medicinal species recorded in Ocotlán  are also found in southern Nuevo Leon, and the leaves, stems, flowers, sap, roots, and fruits are the most common plant parts used. Some of these important medicinal species belong to the genera Aloe, Apium, Bouganvillea, Caesalpinia, Carya, Citrus, Commelina, Lippia, Ocimum, Persea, Psdium, Punica, Rosmarinus, Ruta, Sambucus, Sechium, Solanum, Tecoma, and Tanacetum. Gastrointestinal and skin disorders are a common problem in children in Mexico, and the group of medicinal plant species used by the Zapotec, Maya and Nahuas ethnias to heal them are Chenopodium ambrosioides, Psidium guajava, Artemisia ludoviciana, Ruta chalepensis, Citrus limon, Mentha piperita, Matricaria recutita, Marrubium vulgare, Punica granatum, Turnera diffusa, Anoda cristata, Eucalyptus camaldulensis, Bouganvillea glabra, and Citrus limon, . Some of these plants are used to heal the same disorders in southern Nuevo León. Thirty four Cucurbitaceae species in Mexico have medicinal properties, and in most of cases, almost all of their parts are used for this purpose . Some of these genera such as Cucumis, Cucurbita, Cyclanthera, Sechium, Apodanthera thrieve in Nuevo León, and are used in the same way. Almost 50 species of Quercus are used as medicinal plants to heal tooth problems, gastritis, diarrhea, burns, vaginal infections, heart, kidney diseases, cough, nervousness, muscle pains and diabetes . Some of these uses are also common in southern Nuevo León. Of the 32 species of useful Mimosa species recorded for Mexico , one of them, Mimosa malacophylla is also indigenous to our study area and likewise used in a similar way. In Querétaro, several species of Agave provide maguey sap (mead) to heal some diseases and also to produce a fermented beverage called pulque [50, 51]. In southern Nuevo León, mead and pulque are medicinal and economically relevant medical product used to combat tuberculosis (Mycobacterium tuberculosis) in cattle, it is obtained from Agave lechuguilla. Resin from some Pinus species is used as ointment on wounds, bone fractures, backaches and wounds of domestic animals . In southern Nuevo León Pinus pseudostrobus is used in the same way. Among the most common species used to control o heal diabetes mellitus in Morelos, are Acacia farnesiana, Allium sativum, Artemisia ludoviciana, Baccharis salicifolia, Castela erecta var. texana, Citrus sinensis, Marrubium vulgare, Medicago sativa, Ocimum basilicum, Olea europaea, Opuntia imbricata, Pathernium hysterophorus, Phalaris canariensis, Physalis philadelphica, Punica granatum, Tagates erecta, Taraxacum officinale, Tecoma stans, and Zea mays. Some of these species are also used in the same way in our region; several species such as Lippia graveolens, Prosopis leavigata and Urtica dioica are used by residents to heal different infectious diseases in Huautla, Morelos , the authors state the importance of ethnopharmacology as a guide in the selection of plants for the discovery of bioactive compounds. These plants studied among others, also distribute in southern Nuevo León and are also used to heal several types of diseases. Lophophora williamsi (peyote), and Cannabis sativa (marihuana) are a singular species due to its chemical contents of mescalina, with psicoactivity and potency similar to the salvinorina found on Salvia divinorum, and the tetrahydrocannabinol compounds respectively, in southern Nuevo Leon, Lophophora willliamsi grows abundantly in the scrublands area, especially in Aramberri municipality. It is used to heal rheumatism and muscular pains, but, some residents told us (information recorded in the ethnobiological research, according to local people) that peyote and chaute (Ariocarpus retusus), another species abundantly found in this area, are also used by “hippies” as hallucinogenics. The plants are consumed in a crude form. Both, Lophpophora williamsii in north of Mexico and Salvia divinorum (called Shpherdess, leaves of Mary or Pipiltzintzintli) in the south, are hallucinogenic plants used for healing. Peyote is used crude or also crude and mixed with alcohol and marihuana, while Shepherdess leaves paste is smoked by people in Nuevo León (pers. com., out of the study area), Shepherdess has been reported as marihuan substitute .
Similarities between ethnomedical studies in Mexico and other countries
Several species studied in southern Nuevo León have similar use in different societies worldwide such as Citrus aurantifolia, Eucalyptus spp. Melissa oficinalis, Psidium guajava, and Carica papaya studied in Mozambique . These plants are used as medicinal species to heal cough, headache, high blood pressure, intestinal colic, and toothaches, respectively. The bark, roots, leaves, flowers and fruits of Sambucus nigra, Thymus vulgaris and Olea europaea are common medicinal plant used in the Iberian Peninsula . All of these cultivated plants are present and used in the same way in southern Nuevo León. Of the 145 species of medicinal plants used to heal different diseases recorded in NW Argentina , some of them such as Chenopodium ambrosioides, Erodium cicutarium, Rosmarinus officinalis, and Marrubium vulgare, are also found in southern Nuevo León and are used in similar way. The most common uses of the 184 medicinal species recorded in Camagüey, Cuba were used to heal digestive disorders, skeletal muscle ailments, kidney problems and gynecological disorders, and the plant part most frequently used were leaves and fruit, prepared mainly by decoction and infusion . Those species recorded and their usage are similar to those used in southern Nuevo León; Of the 92 plant species used in veterinary medicine recorded at Navarra Pyrinees , only four wild species, Achillaea millefolium, Plantago major, Rorippa nasturtium-aquaticum, and Taraxacum officinale, and 10 cultivated ones, Allium cepa, A. sativum, Calendula officinalis, Marrubium vulgare, Melissa officinalis, Mentha spicata, Ocimum basilicum, Rosmarinus officinalis, Tanacetum parthenium, and Tymus vulgaris reach their distribution in our study area, however, they are used in a different way.