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Benzocaine

Also known as: Benzocaine local anesthetic, Topical benzocaine

A local anesthetic with limited short-term relief evidence and a serious methemoglobinemia warning; it is not a teething remedy.

Woodcut-style study of an amber jar beside a translucent gel swatch
Editorial illustration

Benzocaine is a local anesthetic used in some oral and external medicines. A toothache trial found short-term relief with specific gels, not treatment of the tooth's underlying problem. FDA warns against teething use and oral products in children under two; serious methemoglobinemia can occur in older users too.3, 1, 2, 6

  • The 2013 study treated 576 participants aged 12 or older with one gel application.3, 4
  • Its pain observation lasted 120 minutes, not a long-term dental follow-up.3
  • Prior uneventful use does not exclude methemoglobinemia on a later exposure.1

What is Benzocaine?

Temporary numbing is a drug effect, not evidence that an infection or cavity has resolved. Oral gel, procedure spray and a medicine for external skin use are different dosage forms. An external-analgesic concentration condition cannot be used as a home recipe or oral-use authorization.1, 5, 6

Where it comes from

Natural sources

  • Not presented as a plant-derived or naturally harvested ingredient.

How it's made

A manufactured medicinal active used in specified formulations; neither a botanical extract nor an edible gel ingredient.

What it does in products

  • Local anesthetic in certain oral-health and external analgesic medicines

Benefits

Short-term toothache relief in a selected trial

limited evidence

Both tested gels outperformed their vehicle on the study's early pain-response endpoint.3, 4, 6

The double-masked trial tested 10% and 20% gels in selected participants with an open tooth cavity. Manufacturer funding and a substantial vehicle response matter; a single observed application cannot exclude rare toxicity or establish treatment of dental disease.

Evidence scope and limitations

Selected toothache gels, FDA's oral-health/teething safety warnings and separate external-analgesic conditions; not all procedure sprays or pain diagnoses.

  • The single-dose, two-hour toothache trial cannot establish chronic-use safety or a rare-event rate.
  • Its indexed primary results were checked; historical regulatory statements in the paper do not replace later FDA actions.
  • Trial population, oral formulation and external-skin concentration conditions must remain separate.
  • Symptom relief cannot establish that the cause of dental pain has been treated.

Evidence last checked: 2026-10-12

Side effects & safety

Methemoglobinemia with impaired oxygen delivery (varies)FDA describes a potentially fatal blood condition, not just skin irritation. Pale, gray or blue coloration, breathlessness, unusual fatigue or rapid heartbeat after exposure requires immediate medical attention.

Safety considerations

  • The selected single-application trial does not clear arbitrary combinations of numbing medicines, formulations or repeated exposures. Check the actual medicine with a pharmacist or clinician.
  • Not for: Do not use oral benzocaine products for teething or in children under two; FDA's teething guidance favors non-drug approaches.
  • Not for: Previous tolerance does not remove the serious blood-disorder warning.
  • Not for: Severe or persistent toothache, fever or pain opening the mouth needs dental or medical assessment rather than continued numbing.
1, 2, 3, 6

Amounts studied & product use

These figures describe research or common product use, not a personal dose or treatment recommendation.

In skincare studies and products

M017 lists benzocaine at 5–20% for defined external-analgesic conditions, not every oral or procedural use. The dental study used specific 10% and 20% gels once. These are different regulatory and research contexts, not instructions to mix raw ingredient or select a personal amount.

5, 3

Regulatory status

  • FDA's 2018 oral-health letter requested discontinuing teething/under-two products and stronger methemoglobinemia labeling for remaining oral uses; current consumer guidance continues the teething warning. M017's external-use conditions are separate. A positive dental trial or OTC availability does not make every oral formulation, age or indication approved.
1, 2, 5

Do not carry an old safety conclusion into a different risk context

The toothache trial reported no methemoglobinemia, but its short, selected observation cannot measure every rare event. FDA's later safety action concerns evidence accumulated beyond that trial. Absence of a case in one experiment is not evidence of zero risk.

Our reading: the endpoint is temporary pain relief while the cause still needs assessment. A tooth may require repair, root-canal treatment or another diagnosis-directed intervention; a numbing ingredient cannot answer which one. The historical oral-product letter should also not be confused with the separate external-analgesic monograph.

3, 1, 6, 5

Frequently asked questions

Does the toothache study support benzocaine for infant teething?

No. It studied people aged 12 and above, while FDA specifically warns against teething use and oral use below age two. Those populations and indications cannot be interchanged.3, 2, 1

Does numbness mean the tooth no longer needs treatment?

No. Relief is not diagnosis or repair. A dentist evaluates the cause; severe pain, symptoms lasting over a day or two, fever or difficulty opening the mouth requires assessment.6

The bottom line

Treat local numbing as a limited medicine effect, not dental care or a teething solution; match route and warnings to the actual product.

References

  1. FDA Letter Regarding Benzocaine. U.S. Food and Drug Administration (2018) · government guidance · May 21, 2018; oral-health product restrictions and methemoglobinemia warnings
  2. Safely Soothing Teething Pain in Infants and Children. U.S. Food and Drug Administration · government guidance · Undated current consumer resource; accessed October 12, 2026
  3. An evaluation of 10 percent and 20 percent benzocaine gels in patients with acute toothaches: efficacy, tolerability and compliance with label dose administration directions. Journal of the American Dental Association (2013) · randomized trial · PMID 23633700; DOI 10.14219/jada.archive.2013.0154; indexed primary abstract, methods, results and disclosures checked; live full text retrieval challenged
  4. Benzocaine Gel Toothache Dose-Response Study. ClinicalTrials.gov (2013) · primary study · NCT00474175; results record updated February 28, 2013; indexed official record checked
  5. OTC Monograph M017: External Analgesic Drug Products for OTC Human Use. U.S. Food and Drug Administration (2023) · government guidance · M017; posted May 2, 2023; benzocaine concentration pertains to external analgesics, not universal oral use
  6. Toothaches. MedlinePlus Medical Encyclopedia (2026) · government guidance · Reviewed February 5, 2026

Revision history

  1. Initial AI-assisted source checks and claim-level citation mapping under the site-authorized publishing workflow. No separate human or independent medical review is claimed.