<![CDATA[Background: Chronic non-communicable diseases (NCDs) are increasing among the Tai Saek ethnic minority in Thailand, yet little is known about how this community culturally interprets and manages NCDs in daily life. Objective: To develop a substantive theory explaining how the Tai Saek ethnic group perceives NCDs and manages them within changing lifestyles. Methods: A grounded theory design based on Strauss and Corbin was used. Eighteen Tai Saek adults (10 with NCDs, 8 without) were theoretically sampled from two villages in Nakhon Phanom province, Thailand. Data were collected from August 2024 to April 2025 through in‑depth interviews, field notes, and theoretical memos, and analyzed with ATLAS.ti using constant comparative analysis. Results: The core category, Cultural Perceptions and Risk Management of NCDs, describes a non-linear process where Tai Saek people balance traditional lifeways, modern influences, and spiritual beliefs. This paradigm model consists of interrelated components: (1) Contextual Conditions, characterized by a dual lifestyle involving modernized agriculture, dietary shifts, generational negotiations, and traditional “Sum Saew” gatherings; (2) Causal Conditions, where individuals construct meanings of NCDs (behavioral vs. genetic) and respond emotionally and behaviorally; (3) Action/Interaction Strategies, which selectively integrate indigenous practices (ancestor worship) with biomedical care; and (4) Consequences, which include both positive adaptation (cultural empowerment) and negative outcomes (delayed biomedical care due to reliance on rituals). Conclusion: The study demonstrates that Tai Saek people do not simply adopt biomedical advice but actively filter it through ancestral beliefs and modern constraints. Nursing care should assess cultural transitions, acknowledge spiritual rituals, and co‑design NCD management plans respecting local wisdom.]]>
