The influence of diet on our health extended beyond basic nutritional needs, certain components in cranberries are showing promising therapeutic potentials due to their unique biochemical properties. This dissertation explores the potential health effects of cranberry (Vaccinium macrocarpon) components, focusing particularly on their role in modulating the gut microbiota and their anti-inflammatory and anti-cancer properties. Cranberries are rich in dietary fiber and polyphenols and have been known for their prebiotic effects that potentially enhance gut health and prevent chronic diseases. This research project includes comprehensive in vitro and in vivo studies and analysis to evaluate the impact of cranberry dietary fiber and polyphenols on anti-inflammation, anti-oxidation, and anti-cancer on cell model, and their influence on gut microbiota composition in a high-fat diet (HFD)-treated mouse model. Our preliminary research indicates that cranberry components such as dietary fibers and polyphenols can significantly affect gut microbiota diversity and functionality, reducing inflammation and lowering cancer cell viability. Our in vivo study results on microbiota modulation, short-chain fatty acids (SCFA) production, and transformation of bile acids (BAs) emphasized the complex interplay between diet, microbiota, and host health, highlighting the therapeutic potential of cranberry components in managing diet-related diseases and enhancing overall metabolic health. Through the detailed studies of these interactions, our research provides valuable insights into functional foods as a natural strategy for health improvement and disease prevention.