Gauze Types: Woven, Nonwoven, Internal-Use and FDA Class

Gauze comes in two main regulatory identities in the United States: nonresorbable gauze for external use (placed on a wound) and nonabsorbable gauze for internal use (used inside the body, with x-ray detectable elements). Clinic staff, buyers and students use this page to tell which gauze is which, and what to confirm on the label. The broader product basics (woven versus nonwoven, sterile versus non-sterile, impregnated formats) are in What Is Gauze?; this page adds the regulatory view.

What is gauze for?

Under the FDA’s external-use definition, gauze is a device “intended for medical purposes, such as to be placed directly on a patient’s wound to absorb exudate” (21 CFR 878.4014). Gauze intended for use inside the body or a surgical incision is defined separately, with a different purpose: to control bleeding, absorb fluid, or protect organs or structures from abrasion, drying or contamination (21 CFR 878.4450). For how gauze sits among other products that cover wounds, see what a medical dressing is.

What is medical gauze?

Medical gauze is open-mesh fabric sold as a device for medical purposes. In the external-use regulation it is “a strip, piece, or pad made from open woven or nonwoven mesh cotton cellulose or a simple chemical derivative of cellulose,” and it may be sterile or nonsterile (21 CFR 878.4014). Internal-use gauze is woven from material that is not less than 50 percent by mass cotton, cellulose or a simple chemical derivative of cellulose (21 CFR 878.4450).

Types of gauze by construction

• Woven mesh. Named in both regulations. Internal-use gauze is defined as woven.
• Nonwoven mesh. Named in the external-use regulation alongside woven mesh.
• Sterile or nonsterile. The external-use regulation covers both. Sterility is a separate property from the regulatory identity, so it is a separate thing to read on the label.

Types of gauze by use and FDA classification

This is the gap in most product listings, which sort by ply, size and count but not by regulatory identity. The table below sets out what the two regulations say.

Type	What the regulation says	Class and premarket status	Source
Nonresorbable gauze/sponge for external use (FDA product code NAB)	Open woven or nonwoven mesh of cotton cellulose or a simple chemical derivative; sterile or nonsterile; placed on a wound to absorb exudate	Class I (general controls); exempt from premarket notification, subject to the limitations in 21 CFR 878.9	21 CFR 878.4014; FDA product classification database, code NAB
Nonabsorbable gauze for internal use	Open mesh fabric for use inside the body or a surgical incision; woven, not less than 50% by mass cotton, cellulose or simple derivative; contains x-ray detectable elements	Class I (general controls); exempt from premarket notification, subject to the limitations in 21 CFR 878.9	21 CFR 878.4450
External-use gauze with added drugs (for example antimicrobial agents), added biologics (for example growth factors) or animal-derived materials	Expressly not covered by the external-use classification in 878.4014	Not classified under 878.4014	21 CFR 878.4014(a)

Boundary rule. “Impregnated” is a different question from “woven versus nonwoven.” The external-use classification excludes gauze that contains added drugs or biologics or is made from animal-derived materials, so an impregnated product cannot be assumed to share the plain-gauze identity above. For a comparison involving a petrolatum-coated gauze, see Xeroform versus petrolatum gauze; for a related product format, see Kling-style conforming dressings.

Types of surgical sponges

Internal-use gauze is the regulatory home of surgical gauze sponges, and the x-ray detectable element is the defining feature in 878.4450. Product-level explainers for specific sponge formats include the Raytec sponge, the drain sponge and the tonsil sponge. This page does not describe how any of them is used in a procedure.

How to check which type you have

These checks follow directly from the regulatory text above. They are a reading aid, not purchasing advice.

1. Intended use. Is the product labelled for external use on a wound, or for internal use? The two have different definitions.
2. X-ray detectable element. Internal-use gauze is defined as containing x-ray detectable elements (878.4450).
3. Sterile or nonsterile. External-use gauze may be either, so the statement on the label tells you which.
4. Added substances. Check whether the product contains a drug, a biologic or an animal-derived material. If so, it falls outside 878.4014.
5. Regulatory class and product code. Plain external-use gauze is Class I under product code NAB in the FDA classification database.
6. Ply and size. These are stated by the manufacturer on the label or datasheet; the regulations quoted here do not set them.

Expiry and shelf-life questions are covered in does gauze expire.

Common mistakes

• Treating “impregnated” gauze as just another weave. Added drugs, biologics or animal-derived materials move it outside the plain external-use classification.
• Assuming that gauze used inside the body is the same as external wound gauze. The regulations define them separately, and only the internal-use definition requires x-ray detectable elements.
• Reading Class I as meaning “no rules.” Class I means general controls and, here, exemption from premarket notification subject to the limitations in 21 CFR 878.9.

FAQ

What is gauze for?

External-use gauze is intended for medical purposes such as being placed on a wound to absorb exudate. Internal-use gauze is intended to control bleeding, absorb fluid, or protect organs or structures inside the body or a surgical incision (21 CFR 878.4014 and 878.4450).

What is medical gauze?

Open-mesh fabric, woven or (for external use) nonwoven, based on cotton cellulose or a simple chemical derivative, supplied as a medical device in sterile or nonsterile form.

Is gauze regulated by the FDA?

Yes. Both plain external-use gauze and internal-use gauze are Class I devices that are exempt from premarket notification, subject to the limitations in 21 CFR 878.9.

What is the difference between woven and nonwoven gauze?

The external-use regulation covers both open woven and nonwoven mesh. The internal-use regulation describes woven material only.

Sources

• eCFR, 21 CFR 878.4014, Nonresorbable gauze/sponge for external use. ecfr.gov. Date checked: 2026-11-01.
• eCFR, 21 CFR 878.4450, Nonabsorbable gauze for internal use. ecfr.gov. Date checked: 2026-11-01.
• FDA product classification database, product code NAB. accessdata.fda.gov. Date checked: 2026-11-01.