John S. Sappington (1776-1856) was an American physician known for developing a quinine pill to treat malarial and other fever diseases in the Missouri and Mississippi valleys, where the disease was widespread. He later used the pill to prevent malaria. Because he both manufactured and sold "Dr. Sappington's Anti-Fever Pills", he became wealthy from his bestseller.
From Maryland and Tennessee, Sappington settled in Missouri after completing medical training and getting married. He married Jane Breathitt, a sister of future Kentucky governor John Breathitt and two other politically connected brothers. As an early pioneer near Arrow Rock, Missouri, Sappington established several businesses to earn money to acquire land. He eventually acquired thousands of acres and became a major planter and slaveholder in the state. In furtherance of his work on treating malarial fever, he wrote The Theory and Treatment of Fevers, (1844), the first medical book printed in Missouri and among the first books published west of the Mississippi River. He imported cinchona bark from Peru, and manufactured and sold quinine pills to treat malaria and other fevers common to the area. His company was eventually a national one.