INTRODUCTION The foundation of the medical field is the medical science of pharmacology since medications are the mainstay of treatment for human ailments. Therefore, in order to optimize the advantages and reduce the hazards of pharmaceuticals to receivers, it is crucial to describe the pharmacological basis of therapies. The primary audience for this pharmacology lecture note is undergraduate students studying health sciences, including nursing, midwifery, health officers, and laboratory technology. However, a lot of the information should also be applicable to other medical practitioners whose line of work includes medication therapy or similar topics. By comprehending the basic scientific tenets of pharmacology, the practitioner is intended to be empowered. To advance comprehension, the effects of archetypal medications on physiological and pathological systems are elucidated in detail. We briefly discuss some similar medications. The national drug list for Ethiopia and the wealth of knowledge gained by instructing numerous health profession students in pharmacology are the two main factors used in the drug selection process. The majority of the chapters conclude with questions that test the reader's comprehension of the ideas presented in the chapter. The chapters begin with a list of objectives to help the reader. The introduction of most sections gives a summary of the topics that will be covered. We hope that this material will be a useful companion in our search of a fundamental understanding in pharmacology, a most intriguing field of therapeutic knowledge. Readers are welcome to consult the references listed for more information.