Tharu Ethnoecology in Pakali, Sunsari, Nepal: Medicinal Plant Knowledge, Home Gardens, and Conservation Willingness

Background Household medicinal-plant knowledge is shaped by social learning and access to plant resources, but household-level evidence on knowledge preservation and transmission from Tharu communities in eastern Nepal remains limited. This study described reported medicinal plant-use, attributed sources of knowledge, sources of splant sources, and stated conservation willingness among Tharu households in Pakali, Sunsari. Methods A cross-sectional survey was conducted with 140 Tharu households in 2025. Face-to-face semi-structured interviews recorded household characteristics, reported plant uses, attributed sources of knowledge and plant material, environmental perceptions, and stated willingness to participate in conservation programs. Descriptive statistics, informant consensus factor, fidelity level, bivariate tests, and binomial logistic regression were used for data analysis. Results Respondents reported 40 putative medicinal taxa. Ocimum tenuiflorum, Zingiber officinale, Aloe vera, Azadirachta indica, Allium sativum , and Curcuma longa were the most frequently mentioned, highlighting the importance of accessible home gardens and household plants in primary healthcare. Ethnomedicinal knowledge was transmitted predominantly through family tradition (81.3%), and home gardens were the primary source of medicinal plants (79.1%). Informant consensus factor (ICF) ranged from 0.14 to 1.00, with the highest agreement observed for burns (ICF = 1.00), followed by colds (0.90), skin diseases (0.87), and body aches (0.86). fidelity level (FL) analysis showed high use specificity for Calotropis gigantea for body aches (100%), Ocimum tenuiflorum for colds (94.88%), Azadirachta indica for skin conditions (85.00%), and Aloe vera for burns (84.84%). Binomial logistic regression indicated that higher income and longer residency were associated with lower stated willingness to participate in medicinal plant conservation, whereas perceiving environmental change as a threat to cultural traditions was associated with greater stated willingness to participate. Conclusions This study provides an updated baseline of reported household medicinal-plant knowledge and use among Tharu households in Pakali, highlighting the importance of family tradition and home gardens in ethnomedicinal practices. The findings contribute contemporary household-level evidence to support future ethnobotanical research and culturally informed conservation initiatives.