There are two ways medicinal maggots may be applied to the chronic wound. The first is to place the maggots directly onto the wound and confine them there with a mesh dressing. This method is sometimes referred to as ‘free-range’ maggot therapy. Alternatively, maggots can be placed on a wound inside a sealed nylon net bag that fully contains them. This application is referred to as maggot therapy with ‘bagged maggots’. In essence the main difference between the two approaches is whether the maggots are confined to the wound as in free-range maggot therapy or fully contained within a nylon net bag.

For maggot therapy in large animals such as horses, livestock, or wildlife, the most effective and convenient way to apply medicinal maggots is via a confinement dressing. Medicinal maggots are placed directly on the wound and a mesh or other fabric is placed over the wound and securely fastened to the surrounding skin. Alternatively, maggots are held in place with a gauze pad and loosely held in place with a bandage over which a tightly woven fabric sleeve is slipped and secured to healthy skin. The materials and methods used to make these confinement dressings depend on the body region. Where the patient is housed in a barn or outdoors, it is less important to prevent maggot escapes. However, it is quite possible to apply confinement dressings that effectively prevent maggot escapes if the animal is a pet and kept indoors. Maggot therapy in cats and dogs may be difficult because the animals often interfere with dressings. Where regular confinement or containment dressings are not accepted by the patient, it is possible to temporarily suture the confinement netting to the healthy skin surrounding the wound for the period of the treatment.

Maggots may also be applied to the wound within a nylon net bag which looks to most people like a tea bag. This is particularly recommended in wounds close to eyes, nose, mouth, ears, and urogenital area and in domestic pets where maggot escapes are more unpleasant than in horses or other livestock kept outdoors. The bag is placed directly onto the wound contacting the necrotic tissue so the maggots can feed through the bag. This total containment is possible because maggots dissolve their food first with digestive juices that they secrete (spit) into the wound before they consume the liquified food. Bags make application and removal of medicinal maggots easy and a more pleasant experience. However, debridement is faster and more effective when maggots are free to move in direct contact with the wound. Bagged maggots remain on the wound for up to four days to achieve the same outcome as free-range maggots.