Medicinal Plants Used by Tai Lao Healers in Roi Et Thailand
Authors: Junsongduang Auemporn , Nabundit Onuma , Chinnawong Pimrudee , Tanming Wattana , Balslev Henrik 
Published: October 2021

Abstract
Background: Local knowledge of herbal medicine in rural communities is rich. This part of cultures plays an important role in societies where knowledge of indigenous medicine and folk healing has been passed down from generation to generation. Most of the knowledge was never written down and much such knowledge has disappeared over time when it was presented orally and through memorization. The objective of this study was to compile knowledge related to medicinal plants used by Tai Lao traditional healers in Roi et province and identify their explicit use in order to preserve the useful wisdom for the people. Methodology: In this study we identify and document medicinal plants and associated ethnobotanical knowledge held by 14 traditional Tai Lao healers. They were selected by snowball and purposive sampling and questioned using semi-structured interviews. Interviews about their knowledge, covered their training, the ailments they treated, the techniques they used, their methods of preparation and, in addition, several healing sessions were observed. During walks in the fields, we searched for the medicinal plant with help from the healers to review and document their availability at each locality and in different habitats around the villages. Use Values (UV) were calculated to estimate the importance of each medicinal plant and Informant Agreement Ratios (IAR) were calculated to understand how widely known the uses were among the healers. Results: We found 146 species of medicinal plants in 127 genera and 60 plant families that were used for medicinal purposes by the 14 traditional healers interviewed. The family with most medicinal plants was Fabaceae (12 spp., 8%) followed by Poaceae (9 spp., 6%) and Zigiberaceae (8 spp., 5%). The most important and widely used medicinal plants were the sedge Cyperus rotundus (UV=0.71) followed by the dicot tree Salacia dongnaiensis (UV=0.64) and the palm Borassus flabellifer (UV=0.42). The most common preparation method was decoction, which was done for 99 species (68%) followed by grinding with water to produce a drink for 29 species (20%). The 14 healers together used medicinal plants to treat 53 specific conditions. Itching had the highest informant agreement ratio (IAR) value among the specific conditions with 0.33 (4 use-reports, 3 spp.). The general category of digestive system disorders had an informant agreement ratio (IAR) value of 0.35 (57 use-reports, 37 spp.) and this category of treatments also had the highest degree of consensus. The most common life form among the medicinal plants was trees (56 spp., 38%), followed by herbs (41 spp., 28%). The medicinal plants were mostly collected in homegardens (60 spp., 41%). The most commonly used plant parts for medicine was the stem which was used for almost half of the species (69 spp., 48%), followed by the roots (54 spp., 37%). The age of the Tai Lao healers varied from 26–87 years. All of them were male. Their age and educations were not correlated with the number of known medicinal plants. The highest number of known medicinal plants was held by a 70 years old healer (55 spp.). Conclusion: Considering the richness of the healers’ pharmacopeia, and the fact that their profession is not being perpetuated, this study points to the urgent need to document the traditional knowledge from the old herbalists before it disappears with the last practitioners in the rural communities.