Civil War Iodine


civil war soldier

The single bloodiest day in US history may have happened on the Antietam National Battlefield in Maryland.  On September 17, 1862, there were 23,000 casualties in just 12 hours to stop the Confederate Army of Northern Virginia's first invasion of the North.  

On that day Confederate General John B. Gordon defied the odds of surviving five bullet wounds thanks to iodine which doctors didn’t know at the time was an antiseptic.  The first bullet from the Union Army hit Gordon in his right calf, another higher up the leg, and then one to the left arm and one to his shoulder.  He fought on until a fifth bullet hit his left cheek, barely missing his jugular vein, and he passed out. He awoke to declare that he would survive. But it was the iodine that his wife applied what seemed to him“ three to four hundred times a day” to the skin of his infected arm that saved him.  

Not only did doctors not know about iodine’s germ-killing abilities, germ theory hadn’t been discovered yet. So, what are the origins of iodine? To develop saltpeter, an ingredient needed for gunpowder during Napoleon’s wars, a French chemist was burning seaweed when he accidentally added too much acid to the ash. It released a violet-colored vapor which he let condense. That turned out to be iodine which they named as a new element. By the Civil War, iodine was standard treatment for wounds, and today, it’s still used to prevent goiters and other thyroid conditions as well as a potent antiseptic!    

We are Drs. David Niesel and Norbert Herzog, at UTMB and Quinnipiac University, where biomedical discoveries shape the future of medicine.   For much more and our disclaimer go to or subscribe to our podcast. Sign up for expanded print episodes at or our podcasts at:  Medical Discovery News ( 

More Information

Gunpowder and Seaweed: The Story of Iodine
In 1811, towards the end of the Napoleonic Wars, France found itself in dire need of gunpowder. Bernard Courtois, a French chemist, was experimenting with using seaweed as an alternative way of processing gunpowder, when he made an amazing discovery. He added too much acid to the suspension of seaweed ash, which produced a violet-colored vapor. After the vapor had condensed into crystals, Courtois analyzed them and then gave some of them to a fellow chemist, Joseph Louis Gay-Lussac, for further study.

The 1862 Battle of Antietam: Casualties and Death Toll
The ferocity of that single day of fighting and the haphazard means by which graves were arranged has made the Antietam death toll hard to truly measure.

Gunpowder: Origins in the East
“Gunpowder,” as it came to be known, is a mixture of saltpeter (potassium nitrate), sulfur, and charcoal. Together, these materials will burn rapidly and explode as a propellant. Chinese monks discovered the technology in the 9th century CE, during their quest for a life-extending elixir. The key ingredient, saltpeter, had been in use by this same culture since the late centuries BCE for medicinal purposes. It was found to be incendiary and immediately applied to warfare.