Pharmaceutical sales representatives must have a very solid understanding of not only how the human body works because while they are not doctors that prescribe the medications, they do need to convince physicians that their medications are the best option for treatment of disease. Doctors will have questions regarding composition, effectiveness, the medications pathway, side effects, etc. and a representative can only answer these if they understand how the body works. They must be able to explain how and why the medication they are presenting offers the best option in pharmaceutical care.