Numbing Gels for Toothache and Mouth Sores: The Benzocaine Warning to Know
Breath & MouthArticleBenzocaine gels and liquids give quick relief for toothaches, gum pain and mouth sores. Their labels warn of methemoglobinemia, a rare but serious drop in blood oxygen, and say to stop after 7 days if pain hasn't improved.
In this article
A throbbing tooth or a painful mouth sore can send you to the dental aisle for a numbing gel. Many contain benzocaine, often at 20%.1 They can help for a few days, but the label carries warnings worth knowing.
The methemoglobinemia warning
Benzocaine labels warn that it may cause methemoglobinemia, a serious condition that lowers the oxygen your blood carries. It can happen even if you’ve used the product before.1
Stop and get emergency care if you notice:1
- pale, gray or blue skin
- headache or fast heartbeat
- shortness of breath
- dizziness or lightheadedness
- unusual tiredness
Other label checks
- Don’t use it if you’re allergic to “caine” numbing medicines such as procaine or benzocaine.1
- Don’t use it for more than 7 days unless a dentist or doctor tells you to.1
- Stop and ask a doctor if mouth pain doesn’t improve in 7 days, or if swelling, rash or fever develops.1
- Use no more than directed, typically up to 4 times a day.1
- Don’t use it on children under 3.1 Keep it out of reach of grandchildren.
A numbing gel is a bridge, not a fix
Toothache usually means something needs a dentist: decay, a cracked tooth, gum disease or an infection. A sore that lasts more than about two weeks should be checked. Our guides to canker sores and oral cancer screening explain when a sore needs a closer look, and our article on sensitive teeth covers common tooth pain.
Checklist
- Read the active ingredient and percentage.
- Use the smallest amount on the sore spot only.
- Count the days, and book a dental visit if pain lasts beyond a few days.
- Know the warning signs of methemoglobinemia.
- Ask your pharmacist about other pain relief options that suit your health.
Try: “I’ve been using a numbing gel on a sore tooth for four days. Can you see me this week, and what can I use for pain until then?”
Is It My Breath? includes a visit script. Use it to note where it hurts, for how long and what you’ve used, before your dental appointment.
This article is for general educational purposes only and is not medical or dental advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Please don't ignore professional advice or delay getting care because of something you read here. Seek emergency care for pale, gray or blue skin, shortness of breath, rapid heartbeat or confusion after using a numbing product. Facial swelling, fever, or a mouth sore lasting more than two weeks needs prompt dental or medical care. If you think you may be having a medical emergency, call 911 or your local emergency number right away. This article discusses a category of products and their labels. It does not evaluate any particular brand or product. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- DailyMed, National Library of MedicineBenzocaine 20% oral gel with menthol, zinc chloride and benzalkonium chloride: Drug Facts (opens in a new tab)abcdefgh
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