Clinical Pharmacology: Clinical pharmacology is the study of drugs in humans. It has a broad scope, from the discovery of new target molecules, to the effects of drug usage in whole populations. Clinical Pharmacology, in theory, has been practiced for centuries through observing the effects of herbal remedies and early drugs on humans. Most of this work was done through trial and error. Since that discovery clinical pharmacology has expanded to be a multidisciplinary field and has contributed to the understanding of drug interaction, therapeutic efficacy and safety in humans.