physiological effect on the cell, tissue, organ, or organism (sometimes the word pharmacon is employed as a term to cover these endogenous and exogenous bioactive species). additional specifically, it's the study of the interactions that occur between a living organism and chemicals that have an effect on traditional or abnormal organic chemistry perform. If substances have healthful properties, they're thought-about prescribed drugs. The field encompasses drug composition and properties, synthesis and drug style, molecular and cellular mechanisms, organ/systems mechanisms, signal transduction/cellular communication, molecular medical specialty, interactions, chemical biology, therapy, and medical applications and antipathogenic capabilities.