"maggot therapy"

I remember reading an account by a prisoner in a WW2 POW camp. A prisoner would come to the 'doctor', it is unclear what his qualifications were, and 'Doc' would unwrap the wound and spend a considerable amount of time examining the festering wound. Then they would wrap it in whatever rags they had on hand. A lot of major, and massively infected, wounds healed after these examinations.

The efficacy of the examination came from Doc observing the flies landing on and depositing their eggs. In a few days the tissue was crawling with maggots and a few days later it was cleaned and on its way to healing.

The maggots only eat dead tissue. It is also said that the maggots excrete chemicals that moderate pain and fight off reinfection by bacteria. Some people reported that maggots in the wound was entirely painless and most people were unaware they were in there until they looked under the covering. Seeing maggots happily dining on their wound was quite shocking to the uninitiated.