Written and maintained by CASRAI Editorial Board
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This page describes products and general use; it is not medical advice.
A medical dressing is a device placed over a wound to cover it, and, depending on the type, to absorb exudate or support a moist wound environment. In US regulation, the common plain dressing types are Class I devices. This guide maps the main classes to the exact wording of the FDA rule that defines them, so clinic staff and buyers can read a product label against the regulation instead of against a marketing category.
Who uses it: clinic and ward staff who stock dressings, buyers and procurement staff who compare product documents, and students learning how dressing categories are defined. For a broader explainer see what a wound dressing is.
What a medical dressing is
FDA does not define “medical dressing” as one device. It defines several dressing types, each in its own section of 21 CFR Part 878 (General and Plastic Surgery Devices). Each definition describes a sterile or non-sterile device; most are intended to cover a wound, and the types differ in purpose and material. A dressing is not the same thing as a bandage; the dressing vs bandage comparison sets out that distinction.
How the FDA definitions are built
Each of the four regulations below has an Identification paragraph (what the device is and what it is intended to do) and a Classification paragraph. Two details matter to anyone reading a product document.
- Sterile or non-sterile. The regulations say “sterile or non-sterile” (the gauze rule says “sterile or nonsterile”). A dressing is not required by these definitions to be sterile, so the label has to state which it is.
- Exclusions. Each rule states that the classification does not include a dressing that contains added drugs such as antimicrobial agents, added biologics such as growth factors, or that is composed of materials derived from animal sources.
Types of medical dressing and their FDA classification
All four types below are Class I (general controls) and are exempt from the premarket notification procedures in 21 CFR part 807, subpart E, subject to the limitations in 21 CFR 878.9. Wording is taken from the Identification paragraph of each section, checked 2026-11-01.
| Type | CFR section | Intended to (per the rule) | Construction (per the rule) |
|---|---|---|---|
| Hydrophilic wound dressing | 21 CFR 878.4018 | Cover a wound and absorb exudate | Nonresorbable materials with hydrophilic properties capable of absorbing exudate (e.g., cotton, cotton derivatives, alginates, dextran, rayon) |
| Occlusive wound dressing | 21 CFR 878.4020 | Cover a wound, provide or support a moist wound environment, and allow exchange of gases such as oxygen and water vapor | A piece of synthetic polymeric material, such as polyurethane, with or without an adhesive backing; nonresorbable |
| Hydrogel wound dressing | 21 CFR 878.4022 | Cover a wound, absorb wound exudate, control bleeding or fluid loss, and protect against abrasion, friction, desiccation and contamination | A nonresorbable matrix of hydrophilic polymers or other material combined with water (at least 50 percent), capable of absorbing exudate |
| Nonresorbable gauze/sponge for external use | 21 CFR 878.4014 | Medical purposes, such as being placed directly on a patient’s wound to absorb exudate | A strip, piece or pad of open woven or nonwoven mesh cotton cellulose or a simple chemical derivative of cellulose |
Product-specific pages on this site: gauze, hydrogel dressings and occlusive dressings.
Silver and other antimicrobial dressings
Because each rule above excludes dressings with added antimicrobial agents, a silver medical dressing is not described by these four Class I identifications. Its regulatory records and the evidence on silver are covered separately in silver wound dressings; they are not repeated here.
What to verify on the label and documents
This checklist follows from the regulation text above and does not rank products.
- Sterile or non-sterile. Confirm the product states which; the FDA definitions allow both.
- Intended use. Compare the product’s stated use with the Identification wording for its type (absorb exudate, support a moist environment, and so on).
- Added drug, biologic or animal-derived material. If the product contains any, it falls outside the four Class I identifications above and its regulatory status needs to be read from its own documents.
- Manufacturer instructions for use. Ask for the current instructions for use; they carry the product-specific directions this page cannot.
Common mistakes
- Assuming every dressing is sterile; the definitions allow non-sterile devices.
- Treating “Class I, 510(k)-exempt” as meaning no FDA rules apply; exemption is subject to the limitations in 21 CFR 878.9 and general controls still apply.
- Applying these four Class I identifications to a dressing that contains an antimicrobial agent or an animal-derived material, which the rules exclude.
Frequently asked questions
What is a medical dressing?
A device placed over a wound to cover it. FDA defines specific types, such as hydrophilic, occlusive and hydrogel wound dressings and nonresorbable gauze, each in 21 CFR Part 878.
Are medical dressings sterile?
Not necessarily. The FDA identifications for hydrophilic, occlusive and hydrogel dressings say “sterile or non-sterile”, and the gauze rule says “sterile or nonsterile”.
Do these dressings need FDA premarket clearance?
The four types in the table are Class I and exempt from 510(k) premarket notification, subject to the limitations in 21 CFR 878.9. Dressings outside those identifications, for example with added antimicrobial agents, are not covered by this statement.
What is a silver medical dressing?
A dressing containing silver as an added antimicrobial agent. The Class I rules above exclude dressings with added antimicrobial agents; see silver wound dressings for its regulatory records and evidence.
Sources
- 21 CFR 878.4018, hydrophilic wound dressing: https://www.ecfr.gov/current/title-21/section-878.4018 (checked 2026-11-01)
- 21 CFR 878.4020, occlusive wound dressing: https://www.ecfr.gov/current/title-21/section-878.4020 (checked 2026-11-01)
- 21 CFR 878.4022, hydrogel wound dressing and burn dressing: https://www.ecfr.gov/current/title-21/section-878.4022 (checked 2026-11-01)
- 21 CFR 878.4014, nonresorbable gauze/sponge for external use: https://www.ecfr.gov/current/title-21/section-878.4014 (checked 2026-11-01)
