Hot and cold : medicinal plant uses in Quechua speaking communities in the high Andes (Callejon de Huaylas, Ancash, Peru)

Ethno-pharmacological relevance: An ethnopharmacological survey has been set up in high altitude Quechua speaking communities dwelling in Callejon de Huaylas (Ancash department, Peru) and in medicinal plant markets in order to document the medicinal plants use of 178 species within the frame of a traditional Andean medicinal system. Materials and methods: A sound ethnopharmacological survey was performed during the years 2011, 2012 and 2013 in different places along Callejon de Huaylas valley in the peruvian Andes, were Quechua speaking communities dwell. Two different methodologies were used: first, plant uses were recorded during walks with informants and in medicinal plant markets held on a regular bases in the area (Huaraz, Carhuaz, Yungay). Secondly, traditional healers (curanderas, curanderos) were interviewed about their practices and healing sessions were observed, in order to understand better the traditional medicinal system as a whole (disease aetiology, diagnosis, treatments, healers). Results: Altogether, 178 medicinal species were collected. Most of the plants found on the market were also found in the wild and vice-versa. Medicinal plant trade is exclusively held by women, selling their merchandise to local people or to big retailer. Plants are classified according their hot or cold virtues, this in accordance with the local conception of the body physiology and disease aetiology, based on a hotcold polarity. Main use notified for medicinal plants is "(bath) against cold", a prophylactic measure against diseases of cold nature. Other uses include culture bound illnesses i.e. susto, aire, nervios, or heart pain, commonly cited in South America. Regarding symptoms, rheumatic/arthritic pain, musculoskeletal traumas, cough, pulmonary and respiratory problems, gastritis and stomach ache, were the most frequently cited. Diagnosis and treatment are intrinsically linked together and mainly based upon divination techniques using egg and cuy (Cavia porcellus L, Caviidae). Discussion and conclusion: Medicinal plants use and traditional medicinal practices are still very vivid in Callejon de Huaylas as highlighted by the abundance of medicinal plants traded in the markets. In this business, women have a key position as healers at the family and community level. Medicinal uses of the majority of the species presented here are reported for the first time. Because medicinal plants sold on the market are collected from the wild and also because high altitude medicinal plants are generally small herbaceous species pulled out with their roots, there is a serious risk of over exploitation and extinction of endemic species