Mupirocin: what it treats, how to use it, side effects
Last updated September 3, 2026.
Mupirocin is a topical antibiotic ointment - it kills the bacteria causing a skin infection right where they are. You may know it as Bactroban. Its job is narrow and it does that job well: bacterial skin infections, nothing else.
What does it treat?
Impetigo - the crusty, contagious skin infection kids pass around - and other bacterial skin infections. It does not work on fungal or viral infections, which is why the diagnosis comes before the tube.
How do you take it?
Wash the affected skin thoroughly, then apply a small amount - a thin film - three times a day for 1 to 2 weeks, exactly as prescribed. A sterile gauze dressing over the area is allowed. Two hard rules: never in the eyes, and never on burns unless your doctor specifically told you to. Finish the full course even when the skin looks better - stopping an antibiotic early is how resistant bacteria get trained. Missed application: apply when you remember unless the next one is close; never double up.
Side effects to know
- Common: burning, stinging, pain, itching, or rash at the application site - report any that are severe or refuse to settle.
- Serious - call your doctor: any sign of an allergic reaction like hives or a spreading rash.
Who should not take it?
Anyone allergic to mupirocin. Skin only - eyes are out, burns only by explicit direction. Tell your doctor about everything else you take so interactions stay screened, and if you become pregnant while using it, call your doctor.
When is it an emergency?
Hives, facial or throat swelling, or trouble breathing after applying it is a 911 call - topical does not mean incapable of a systemic allergic reaction. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
Why do I have to finish the whole course of mupirocin?
Same reason as any antibiotic: the skin looks healed before the bacteria are actually gone. MedlinePlus says use it exactly as directed - typically three times a day for 1 to 2 weeks - and stopping early lets the toughest bacteria survive and come back harder. For a topical antibiotic, the course is the treatment, not the visible improvement.
Why can't I put mupirocin in or near my eye?
MedlinePlus is direct: do not apply mupirocin to your eyes. The ointment base and the drug concentration are built for skin. If the infection is anywhere near the eye, that is a doctor visit for an eye-appropriate formulation, not a careful workaround with the tube you have.
Why can't I use mupirocin on a burn?
Not without your doctor explicitly saying so - that is the label rule. Burns are a different kind of wound than the bacterial skin infections mupirocin is approved for, and what a burn needs depends on its depth and whether it is actually infected. Burn plus signs of infection - spreading redness, warmth, pus - is a doctor visit, not a self-treat.
Will mupirocin work on my fungal or viral skin problem?
No - MedlinePlus states it treats impetigo and other bacterial skin infections and is not effective against fungal or viral infections. Ringworm, cold sores, and shingles all need different drugs. If the diagnosis is uncertain, that is the question to settle before the tube gets opened, because two weeks of the wrong ointment is two weeks of the real problem growing.
The infection looks better after three days. Can I stop?
Looking better is the drug working, not the drug finishing. The 1-to-2-week course exists because the bacteria outlast the symptoms. Run the full schedule your prescriber wrote, then let them decide whether anything more is needed at the follow-up.
What happens if I miss a dose of mupirocin?
Apply it as soon as you remember, unless it is almost time for the next one - then skip it and never apply a double amount. Three-times-daily drugs forgive one gap. Anchoring the applications to meals makes gaps rare.