This thesis provides a comprehensive review from clinical and pharmacological perspectives on diuretics, with a primary focus on their role in managing cardiovascular diseases. It outlines the classification, mechanisms of action, pharmacokinetics, side effects, and contraindications of major diuretic classes, including carbonic anhydrase inhibitors, loop diuretics, thiazides, potassium-sparing diuretics, and osmotic diuretics. Additionally, it discusses drug interactions and clinical applications in conditions such as hypertension, heart failure, and chronic kidney disease. Emerging therapies, such as vasopressin receptor antagonists and SGLT2 inhibitors, are also examined for their potential clinical benefits. The thesis aims to support evidence-based understanding and rational use of diuretics in medical practice.