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Neomycin: Uses, How It Works, and Safety Information

Last reviewed: December 2025

Overview

Neomycin is a topical antibiotic used to prevent infection in minor cuts, scrapes, and burns. It belongs to the aminoglycoside class of antibiotics and is effective against a wide range of bacteria, particularly gram-negative organisms.

Neomycin is available over-the-counter, most commonly in combination products like “triple antibiotic ointment” (neomycin, bacitracin, and polymyxin B) or “double antibiotic ointment” (neomycin and polymyxin B). It is less commonly used alone due to its higher rate of allergic reactions compared to other topical antibiotics.

How It Works

Neomycin is an aminoglycoside antibiotic that works by:

  • Inhibiting protein synthesis — Binds to bacterial ribosomes and prevents bacteria from making essential proteins
  • Causing bacterial cell death — Without the ability to produce proteins, bacteria cannot survive or reproduce
  • Broad-spectrum coverage — Effective against many gram-negative bacteria (like E. coli) and some gram-positive bacteria

When applied topically, neomycin acts locally on the skin surface with minimal absorption into the bloodstream.

Common Uses

Neomycin is used to prevent infection in:

  • Minor cuts and scrapes — Everyday wounds from accidents
  • Minor burns — First-degree burns and minor thermal injuries
  • Abrasions — Skin injuries from friction
  • Surgical incisions — Minor wound care after procedures (under medical guidance)
  • Skin grafts — Infection prevention at graft sites (medical supervision required)

Like other topical antibiotics, neomycin is for prevention of infection, not treatment of established infections.

When to See a Doctor

Seek medical attention if you experience:

  • Signs of infection — Increasing pain, swelling, redness, warmth, or pus
  • Fever — Especially with wound changes
  • Deep or puncture wounds — May need professional cleaning
  • Animal or human bites — Higher risk requiring evaluation
  • Wounds not healing — No improvement after 1 week
  • Allergic reaction — Rash, itching, or swelling spreading beyond the wound
  • Serious burns — Burns larger than your palm or affecting sensitive areas

Important Considerations

  • High allergy potential — Neomycin is the most common cause of allergic contact dermatitis among topical antibiotics
  • Cross-reactivity — If allergic to neomycin, you may also react to related aminoglycosides (gentamicin, tobramycin)
  • External use only — Do not apply to eyes, inside nose or mouth
  • Avoid on large areas — Risk of absorption increases with wound size
  • Not for ear drops if perforated eardrum — Neomycin ear drops can cause hearing damage if used with a perforated eardrum
  • Short-term use — Typically 7 days or less

Sources

  • FDA OTC Drug Monograph — Topical Antimicrobial Drug Products
  • American Contact Dermatitis Society — Allergen of the Year
  • UpToDate — Aminoglycoside antibiotics
  • MedlinePlus — Neomycin Topical
Last reviewed: December 2025