How Maggot Therapy Works

Know Your Maggots
Several hundred sterile maggots are introduced into this patient's wound and secured in place by a tape dressing, to remove dead tissue.
Several hundred sterile maggots are introduced into this patient's wound and secured in place by a tape dressing, to remove dead tissue.
Karen Mower/Getty Images

Before you go dropping fly larvae into your open wounds, there's a few things you'd perhaps like to know. Who are these maggots? Where do they come from? And, of course, how do they work?

As flies develop from eggs to adults, they stop off at a few stages along the way. In about half of fly species, this includes a larval phase unofficially known as a maggot – a pale, wormlike creature with a simple mission: eat, store energy and grow.

Not all maggots are suited for medicine: Some prefer to eat plants, while others carry diseases. Still others, such as the nightmare-fueling Internet celebrity Dermatobia hominis, aka the human botfly, develop inside living flesh.

No, the fly you want is Lucilia sericata, aka the common green bottle fly or sheep blowfly. Fans of "CSI" and of body farms, research centers that study corpse decay under a variety of conditions, know this creature for its worth in pinning down time of death. Because L. sericata lays its eggs in bodies very soon after a person's demise, experts can link their larval growth to elapsed time since death [source: Anderson and Kaufman].

Perhaps that's not the best picture to paint if we want to sell you on their healing power, but it makes the critical point, which is that L. sericata larvae only eat necrotic (dead) tissue and bacteria, not living flesh.

How do they do it? Contrary to what some have reported, they don't chew on you. In fact, they have no teeth. Instead, these maggots excrete enzymes that break down complex proteins into simpler, more digestible ones. They also use mouth hooks to scrape or grind the tissue as needed. Maggots also likely bump up oxygen in the wound and augment cell growth [sources: Gabrielsen, Anderson and Kaufman].

So where's your immune system in all of this? Your body doesn't attack the maggots because their secretions also break down complement proteins, part of the body's immune response. In fact, according to one study, these secretions reduce complement protein levels by 19-55 percent [source: Gabrielsen]. This is in fact a good thing. Too much complement activation can cause chronic inflammation, which can increase the chance of infection by keeping a wound open [source: Arnold]. Remarkably, the efficacy of this secretion appears not to taper off over time. In fact, researchers are now at work turning it into a drug.

Yet, for all their success, maggots had been enjoying a retirement from their medical practice since the 1940s, when the growth in antibiotic drugs brushed them aside. So what brought them out of retirement?