Maggots found on corpses are useful to forensic scientists, specifically forensic entomologists. Maggot species can be identified by various means such as their anatomy and by matching their DNA. Maggots of various species of flies visit corpses and carcases at fairly well-defined times after death, and so do their predators such as beetles in the family Histeridae. Thus, the presence or absence of particular species of fly maggots and other scavenger insects provide evidence as a basis for estimation of the time since death, and sometimes other details such as the place of death.
Some species of maggots are bred commercially; they are sold as bait in angling, and as food for carnivorous pets such as some fishes, reptiles, and birds[citation needed.
Fly larvae can be used as a biomedical tool for wound care and treatment. Maggot debridement therapy (MDT) is the use of blow fly larvae to remove the dead tissue from wounds, most commonly being amputations. Historically, this has been used for centuries, both intentional and unintentional, on battlefields and in early hospital settings. Removing the dead tissue promotes cell growth and healthy wound healing. The larvae also have biochemical properties such as antibacterial activity found in their secretions as they feed. These medicinal maggots showed to be a safe and effective treatment for chronic wounds of ambulatory patients.
In food production, certain cheese varieties, such as casu marzu, are exposed to flies known as cheese skippers, members of the family Piophilidae. The digestive activities of the fly larvae soften or liquefy the cheese and modify the aroma as part of the process of maturation.