Mupirocin Ointment: what it does and what to watch
Also known as: Topical antibiotic ointment, Bacterial skin infection ointment · Topical antibiotic ointment · Updated 2026-08-20 · Educational — not medical advice
In plain language: This ointment blocks a specific enzyme that bacteria need to build proteins, stopping susceptible bacteria from growing and allowing the skin's healing process and immune defenses to clear the infection. It's applied directly to the affected area, and because it works differently from many other antibiotic classes, it's often chosen for skin infections caused by bacteria resistant to more common oral antibiotics.
What it's used for
- Impetigo and other superficial bacterial skin infections
- Minor infected cuts, abrasions, or wounds
- Nasal application to reduce certain bacteria colonizing the nostrils, when specifically directed
Common side effects
- Mild burning or stinging at the application site
- Itching
- Localized redness
- Dryness of treated skin
- A sensation of stickiness or tenderness at the site
Get medical help if…
Allergic contact reaction with worsening redness, swelling, or rash beyond the treated area
Superinfection with a different organism, such as a fungus, if the ointment is used for a prolonged period
Absorption of the ointment's polyethylene glycol base through large open wounds, which in people with significantly reduced kidney function could theoretically affect how it's cleared from the body
Signs the treated infection is spreading rather than improving, such as increasing warmth, swelling, or fever
Lab values it can move
Few guides tell you this part: medicines show up in blood work. If you take Mupirocin Ointment and a value below looks off on your report, this may be part of the story — never stop a medicine without your doctor.
This ointment's inactive base ingredient can be absorbed through large open wounds; in people with significant kidney impairment being treated over extensive wound areas, kidney function is sometimes considered when deciding on treatment duration.
CreatinineGood to know
- Use only on the skin areas directed; this ointment is not intended for the eyes or for deep puncture wounds
- Complete the recommended course length rather than stopping as soon as visible improvement appears
- Avoid applying to very large areas of broken or raw skin without medical guidance, given limited absorption data in that setting
- Wash hands before and after application, and avoid touching the treated area unnecessarily to reduce spread of infection
- Seek medical review if the infection doesn't improve within a few days or appears to be spreading
Questions people ask
Can I use this ointment on a large open wound?
This ointment is generally intended for smaller, superficial skin infections such as impetigo or minor infected cuts. Its inactive base ingredient can be absorbed more than usual through large open wounds, which is a particular consideration for people with reduced kidney function. For larger or deeper wounds, it's best to have a prescriber assess the most appropriate treatment.
Why would a doctor use this in my nose instead of on skin?
In certain situations, a prescriber may direct nasal application to reduce specific bacteria that live in the nostrils without causing symptoms, particularly before some medical procedures or to address recurrent skin infections linked to nasal carriage. This use is more specialized and should only be done exactly as directed, since it differs from typical skin-infection use.
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