Pharmacology is a science.
Pharmacology is the branch of biology concerned with the study of drug action , where a drug can be broadly defined as any man-made , natural , or endogenous ( from within body ) molecule which exerts a biochemical or physiological effect on the cell , tissue , organ , or organism ( sometimes the word pharmacon is used as a term to encompass these endogenous and exogenous bioactive species ) . In either field , the primary contrast between the two are their distinctions between direct-patient care , for pharmacy practice , and the science-oriented research field , driven by pharmacology . Pharmacology as a scientific discipline did not further advance until the mid-19th century amid the great biomedical resurgence of that period . Pharmacology developed in the 19th century as a biomedical science that applied the principles of scientific experimentation to therapeutic contexts .