The use of maggot therapy is experiencing a revival in the treatment of problem wounds. Although this alternative therapy is ancient, little scientific research has been aimed at standardizing this therapy. The purpose of our investigation was to determine the debridement efficiency of this therapy, i.e., to compare the use of freely crawling maggots with maggots in a Biobag and to estimate the amount of maggots needed for debridement. We designed an artificial wound model and investigated the rate of decomposition of porcine tissue. Two application alternatives were compared, each being carried out either for 3 or for 4 days, (1) maggots that were allowed to crawl freely over the substrate and (2) maggots confined to a Biobag with no direct contact with the wound. We found that a single maggot was capable of debriding approximately 0.15 g of dead tissue per day. Assuming an absolute difference of <0.05 g per day and maggot as clinically irrelevant, the debridement efficiency of free maggots appears to be similar to those in a Biobag. We were able to determine for the first time the average debriding ability of maggots and thus provide the clinician with data that may help to optimize the maggot therapy by facilitating more exact approximations of the number of maggots needed. Furthermore, the result that the maggots in the Biobag are equal to free maggots in their debriding efficiency will promote its use, especially with respect to the time saved for changing of the dressings. Also, we were able to show that no direct contact is necessary between the maggots and the wound surface, proving that the mechanical crawling effect appears to be neglectable. Because significantly more tissue was metabolized after 4 than after 3 days, application intervals of 4 days appear more appropriate than those of 3 days.