Cholestyramine resin is primarily used in the medical field to manage high cholesterol levels. It works by binding to bile acids in the intestine, preventing their reabsorption and promoting their excretion. This process forces the liver to use cholesterol to produce more bile acids, thereby reducing the overall cholesterol levels in the blood. It is often prescribed to patients with hyperlipidemia or those at risk of cardiovascular diseases.

Additionally, it is effective in treating certain types of diarrhea, particularly bile acid diarrhea, by absorbing excess bile acids in the gut. It can also be used to relieve itching caused by partial biliary obstruction. The resin is typically administered orally as a powder mixed with water or other liquids. Patients are advised to follow specific dosing instructions and maintain adequate hydration to avoid gastrointestinal side effects such as constipation or bloating.