Yellow Jack is a 1938 film released by Metro-Goldwyn-Mayer based on the 1934 play Yellow Jack. Both were cowritten by screenwriter Sidney Howard and Paul de Kruif, a microbiologist and author.

Plot

Major Walter Reed of the United States Army works to diagnose and treat yellow fever (called “yellow jack”) in Cuba at the end of the 19th century. U.S. Army Medical Corps doctors study the theory of Cuban doctor Carlos Finlay that the disease is caused by bites from infected Aedes aegypti mosquitoes, a concept that had previously been ridiculed. Soldiers volunteer to be research subjects by allowing themselves to be bitten and contract the deadly disease, for which no cure was known.