Negative-pressure wound therapy (NPWT), also known as a vacuum assisted closure (VAC), is a therapeutic technique using a suction pump, tubing, and a dressing to remove excess exudate and promote healing in acute or chronic wounds and second- and third-degree burns. The therapy involves the controlled application of sub-atmospheric pressure to the local wound environment using a sealed wound dressing connected to a vacuum pump. The use of this technique in wound management started in the 1990s and this technique is often recommended for treatment of a range of wounds including dehisced surgical wounds, closed surgical wounds, open abdominal wounds, open fractures, pressure injuries or pressure ulcers, diabetic foot ulcers, venous insufficiency ulcers, some types of skin grafts, burns, sternal wounds. It may also be considered after a clean surgery in a person who is obese.

NPWT is performed by applying a vacuum through a special sealed dressing. The continued vacuum draws out fluid from the wound and increases blood flow to the area. The vacuum may be applied continuously or intermittently, depending on the type of wound being treated and the clinical objectives. Typically, the dressing is changed two to three times per week. The dressings used for the technique include foam dressings and gauze, sealed with an occlusive dressing intended to contain the vacuum at the wound site. Where NPWT devices allow delivery of fluids, such as saline or antibiotics to irrigate the wound, intermittent removal of used fluid supports the cleaning and drainage of the wound bed.

In 1995, Kinetic Concepts was the first company to have a NPWT product cleared by the US Food and Drug Administration. Following increased use of the technique by hospitals in the US, the procedure was approved for reimbursement by the Centers for Medicare and Medicaid Services in 2001.