INTRODUCTION: Few studies have investigated the association between Life's Essential 8 (LE8) and abnormal bowel health. We aimed to investigate the relationship between LE8 and diarrhea and constipation in the adult population of the United States. METHODS: This cross-sectional study, based on population data, used information from the National Health and Nutrition Examination Survey conducted between 2005 and 2010. Diarrhea and constipation were classified based on Bristol Stool Form Scale and stool frequency. LE8 score is composed of 4 health behaviors (diet, physical activity, nicotine exposure, and sleep health) and 4 health factors (body mass index, blood lipids, blood glucose, and blood pressure) and is classified into low (0-49), moderate (50-79), and high (80-100) cardiovascular health groups. Weighted logistic regression and restricted cubic splines were used to analyze the relationship between the LE8 score and abnormal bowel health. RESULTS: The study comprised 12,369 participants aged 20 years or older, among whom 1,279 (9.7%) had constipation and 1,097 (7.6%) had diarrhea. After adjusting for potential confounders, we observed negative associations between LE8 scores and diarrhea (odds ratio: 0.60, 95% confidence interval: 0.39-0.93), whereas the association between LE8 scores and constipation was not statistically significant (odds ratio: 0.82, 95% confidence interval: 0.59-1.13). In addition, health behavior scores and health factor scores were associated with constipation. DISCUSSION: Higher LE8 levels are associated with a lower incidence of diarrhea, but not constipation.