How did they treat diarrhea during the Civil War?

Battlefield Medicine: How Diarrhea Was Treated During the Civil War

During the American Civil War, disease claimed far more lives than combat, with diarrhea and dysentery ranking among the most pervasive and lethal threats facing soldiers on both sides. In unsanitary and overcrowded military camps, poor hygiene and contaminated water caused these illnesses to spread rapidly, forcing army physicians to rely on 19th-century treatments that often proved as dangerous as the conditions themselves.

To manage severe symptoms, field surgeons relied heavily on quinine, a compound typically used against malaria, alongside opium to dull excruciating abdominal spasms and pain. Beyond pain management, doctors routinely administered aggressive purgatives and chemicals. Popular remedies included calomel—a toxic mercury-based compound—as well as blue mass, strychnine, castor oil, turpentine, silver nitrate, and ipecac.

While intended to cleanse the body or rebalance internal fluids according to the era's medical theories, these harsh substances caused extreme side effects, including severe mercury poisoning and intestinal damage. Ultimately, the desperate attempts to treat dysentery underscored the primitive state of battlefield medicine before the advent of modern germ theory.