This book provides a thorough introduction to the principles of pharmacology and the mechanisms of drug action. It covers the basic concepts of drug absorption, distribution, metabolism, and excretion. The book also addresses the therapeutic and adverse effects of various drug classes. It is intended for medical students, pharmacists, and healthcare professionals, offering essential knowledge for understanding drug interactions and patient care. By presenting fundamental pharmacological principles, the book seeks to improve the safe and effective use of medications in clinical practice.