Maggot debridement therapy is the intentional application of live, “medical-grade” fly larvae to wounds in order to effect debridement, disinfection, and ultimately wound healing. Controlled studies demonstrate the efficacy and safety of maggot therapy. In the 21st century, eighty years after William Baer presented his groundbreaking work treating bone and soft tissue infections with live maggots, thousands of therapists around the globe have rediscovered the benefits of maggot therapy. The renaissance in maggot therapy is due in large part to recent technological advancements that have solved or minimized many of the treatment’s earlier drawbacks

In a bloody battle during World War I, two wounded soldiers were stranded on the battlefield in France, hidden and overlooked under some brush. Suffering femur fractures and flesh wounds around their scrotum and abdomen, they lay abandoned without water, food, or shelter for a whole week. At the time, outcomes for these kinds of wounds were poor: Patients with compound femur fractures had a 75 to 80% mortality rate. By the time the soldiers were rescued and brought to a hospital base, orthopedic surgeon William Baer expected their wounds to be festering, and their conditions fatal. But much to his surprise, neither showed any signs of fever, septicaemia, or blood poisoning. 

When his team removed the soldiers’ clothing, they discovered that their flesh wounds were filled with thousands of maggots, or baby flies—little larvae with a massive appetite for decaying matter. Baer was repulsed by the sight, and the team quickly washed off the wriggling maggots. “These wounds were filled with the most beautiful pink granulation tissue that one could imagine,” Baer later wrote in a 1931 report in the Journal of Bone and Joint Surgery. Maggots have long been associated with death, but in this case, they were helping the soldiers stay alive. As these insects were simply tucking in for their typical meal of dead, decaying flesh, they were inadvertently aiding the soldiers by cleaning their wounds, keeping infection at bay. The soldiers recovered—saved by their tiny, wriggling “friends which had been doing such noble work,” Baer wrote. Baer’s paper is one of the first reports of maggots used in medicine, but these insects have been found healing wounds for thousands of years, with references in the Old Testament and in ancient cultures of New South Wales and Northern Myanmar. In 1997 on Science Friday, authors Robert and Michèle Root-Bernstein regaled the audience with tales of maggots and other historical medical practices. 

After the war, Baer brought his observations back to America, experimenting with applying maggots to surgical operations on chronic osteomyelitis, a debilitating bone disease that can persist for years. Some of his studies were more successful than others; in his early trials attempting to replicate what he saw on the battlefield, he collected unsterilized maggots from rotting raw beef he left outside, which led to some secondary bacterial infections. But once Baer established which species of fly worked best, and how to sterilize them, he observed that maggots could cure patients’ lesions and sores within months—fast compared to other available treatments, which could take a decade.