Pharmacology is a medical science that forms a backbone of the medical profession as drugs form the corner stone of therapy in human diseases. Therefore, it is of utmost importance to describe the pharmacological basis of therapeutics in order to maximize the benefits and minimize the risks of drugs to recipients. This lecture note on pharmacology is primarily a note for undergraduate health science students such as health officer, nursing, midwifery and laboratory technology students. However, other health professionals whose career involves drug therapy or related aspects should also find much of the material relevant.