Canker Sore Treatments During Pregnancy — What's Safe, What Isn't

TL;DR

Most of the simple things that help a canker sore are fine during pregnancy. Barrier patches contain no drug and are the safest option. A small dab of benzocaine (Orajel) on one sore is low-risk for adults. Honey and salt water rinses are safe. A short course of prescription steroid paste on a single sore is generally considered acceptable, but tell your OB. Correcting a low B12, iron or folate level is safe and good for the pregnancy too. Chemical cautery (Debacterol, silver nitrate, Oral Medic) has no pregnancy data at all, so it's a conversation for your dentist and OB, not something to do at home. Oral steroids, colchicine, thalidomide and dapsone are avoided. Many women get fewer sores while pregnant, though the research on that is thin, and sores often come back in the weeks after delivery, so it's worth having a plan ready.

The safest place to start is a barrier patch:

Quick Reference: What's Safe in Pregnancy

What Is Safe During Pregnancy

Barrier patches

Canker Cover and similar dissolving patches stick to the sore and seal it off from food, drinks and your teeth. They're made of gel-forming polymers like carboxymethylcellulose, with no medicine in them, so nothing gets into your bloodstream. That makes them the safest canker sore product there is, pregnant or not. They give several hours of pain relief per patch, which can be the difference between eating a meal and skipping it. See Best Canker Sore Patches for how the different brands compare.

Benzocaine (Orajel, Anbesol)

Benzocaine numbs the sore. A small amount on one ulcer gets very little into the blood, dentists have used it in pregnant patients for decades, and it isn't a known cause of birth defects.

In 2018 the FDA warned about benzocaine and methemoglobinemia, a rare condition where the blood can't carry oxygen properly. The cases behind that warning were mostly young children and heavy use. For an adult putting a small dab on one sore before a meal, the dose is far lower. Use it when you need it, not as an all-day routine, and don't use it on teething babies after they're born.

Salt water rinse

A quarter to half a teaspoon of salt in 8 oz of warm water, swished gently for 30 to 60 seconds, is safe throughout pregnancy. It rinses food and acidic residue off the sore without much sting. It isn't meaningfully antibacterial at that strength, and no trial has tested it for canker sores, so think of it as comfort, not treatment. More in Salt Water Rinse for Canker Sores.

Baking soda rinse

Half a teaspoon of baking soda in a glass of water is safe in pregnancy. There's no evidence it helps a canker sore heal; see Baking Soda for Canker Sores. It does have one real use during pregnancy: if you're throwing up from morning sickness, rinsing with baking soda and water afterward neutralizes stomach acid and protects your tooth enamel. Wait a while before brushing, because brushing right after vomiting scrubs acid into softened enamel.

Honey

Honey on the sore is safe during pregnancy. The botulism concern with honey applies to babies under a year old, not to adults or to a baby before birth. Honey is also one of the few home remedies with trials behind it: in several small randomized trials, honey did as well as or better than a prescription steroid paste for canker sores (El-Haddad et al., 2014 — PMID: 25019115; Ghalwash et al., 2025 — PMID: 39723829). Any good honey works for this. Manuka is the type with the strongest wound-healing track record. See Manuka Honey for Canker Sores.

Chemical cautery: ask first

Debacterol, silver nitrate and Oral Medic (sold in the US as Hybenx) are caustic agents. They burn the surface of the sore, which kills the exposed nerve endings and usually stops the pain quickly. The amount used is tiny and applied to a few millimeters of tissue, so very little is likely to be absorbed. But "likely" is all anyone can say. None of these products has been studied in pregnancy, and they can damage healthy tissue if used wrong.

Our view: if a sore is bad enough that you're thinking about cautery while pregnant, have a dentist look at it and check with your OB. Don't try these at home. For background on how they work and what to expect, see our Debacterol review, why Debacterol works better at the dentist, and silver nitrate for canker sores.

Use With Caution or Avoid

Steroid paste (triamcinolone, Kenalog in Orabase)

Triamcinolone paste is the most commonly prescribed treatment for canker sores, and it does help them heal faster (see Canker Sore Treatment). Very little is absorbed from a small patch of the mouth, and the main worries about steroids in pregnancy are about pills and injections, especially in the first trimester. A thin layer on one sore for a few days is generally considered acceptable. Using it for weeks, or using stronger steroids, is a different story. Either way, tell your OB. If you have leftover paste from an old prescription and a sore is miserable, ask before using it rather than after.

Dexamethasone rinse

This prescription steroid rinse is stronger than triamcinolone paste, and because you swish it, the whole mouth is exposed instead of one spot. It's less preferred in pregnancy. Don't use it without your OB's go-ahead.

Oral steroids (prednisone, prednisolone)

Pooled case-control studies linked steroid pills in the first trimester to a higher risk of cleft lip and palate. A prospective group of exposed women in the same analysis showed no increase in major birth defects, and the absolute risk is low (Park-Wyllie et al., 2000 — PMID: 11091360). Even so, a canker sore, however painful, isn't a threat to the mother's health, so oral steroids are generally avoided for canker sores in pregnancy. The exception is severe disease managed by a specialist together with your OB.

Amlexanox (Aphthasol)

Amlexanox paste shortens healing time, but there's no pregnancy safety data, and the brand was discontinued in the US. With no data and limited availability, it's best avoided while pregnant. See Aphthasol Is Gone.

Colchicine

Colchicine is used for severe recurring canker sores, often in Behçet's disease. It interferes with cell division and has caused birth defects in animal studies. It's generally avoided for canker sores during pregnancy. If you already take it for another condition, don't stop on your own; talk to the doctor who prescribed it.

Thalidomide

Thalidomide is sometimes used for severe major canker sores and Behçet's disease. It must never be used in pregnancy. It caused one of the worst drug-related birth defect disasters in history, and in the US it's only available through a strict program that requires reliable contraception.

Dapsone

Dapsone is used for some hard-to-treat cases. Near the end of pregnancy it can harm the baby's red blood cells. Avoid it while pregnant, and ask before using it while breastfeeding.

Hydrogen peroxide

Hydrogen peroxide isn't a pregnancy risk, but it kills the cells your mouth needs to heal, so it works against a canker sore whether you're pregnant or not. Skip it. See Hydrogen Peroxide for Canker Sores.

Nutrition in Pregnancy and Canker Sores

Pregnancy raises your need for several nutrients that are linked to canker sores. This is the part of canker sore care that's not a tradeoff at all: fixing a deficiency helps both you and the pregnancy. For the full picture, see Best Supplements for Canker Sores.

Folate

Folate needs go up by half in pregnancy, from 400 to 600 mcg a day, and every prenatal vitamin contains it to prevent neural tube defects. Low folate is also one of the deficiencies linked to recurring canker sores; see Folate and Canker Sores. If your sores improved after you started a prenatal vitamin, the folate may be part of the reason.

A note on folic acid versus methylfolate: outside pregnancy, some people prefer methylfolate. During pregnancy, folic acid is the form proven to prevent neural tube defects, and the CDC says people with MTHFR gene variants can process it and should still take it. Don't swap out your prenatal's folic acid without talking to your OB.

Iron

Iron needs rise from 18 to 27 mg a day in pregnancy to support your expanding blood volume and the baby. Iron deficiency is the most common nutrient deficiency in pregnancy. Prenatal visits usually check hemoglobin, but ferritin, which shows your iron stores, often isn't checked, and stores can run low well before you're anemic. If you're getting canker sores while pregnant, ask for a ferritin test. See Iron Deficiency and Canker Sores.

If testing shows you're low, your OB will recommend a dose. Iron bisglycinate tends to be easier on the stomach than ferrous sulfate, which matters when constipation and nausea are already part of the picture:

Vitamin B12

B12 needs rise only slightly (2.4 to 2.6 mcg a day), and most prenatals contain enough for most people. The people who need more are those who absorb it poorly: anyone on an acid reducer, with pernicious anemia, with past stomach surgery, or with Crohn's disease. Vegetarians and vegans also often need more than a prenatal provides.

B12 is the supplement with the best evidence for preventing canker sores. In a placebo-controlled trial, 1,000 mcg under the tongue every night for six months left 74% of people ulcer-free in the final month, compared with 32% on placebo (Volkov et al., 2009 — PMID: 19124628). B12 is water-soluble and very safe at that dose, and it's appropriate during pregnancy. The form (methylcobalamin or cyanocobalamin) doesn't seem to matter much. See Vitamin B12 for Canker Sores.

Zinc

Zinc needs in pregnancy are about 11 mg a day, and the upper safe limit is 40 mg a day from all sources. Most prenatals already contain zinc, often 11 to 25 mg, so check the label before adding more. Only add a separate zinc supplement if testing shows you're low, and keep your total under 40 mg. See Zinc for Canker Sores.

Pregnancy Can Add New Triggers

Even if pregnancy calms your immune system down, it brings a few things that can irritate the mouth.

Morning sickness and heartburn. Stomach acid in the mouth stings an open sore, and both vomiting and reflux are common in pregnancy. Rinse with water or a baking soda rinse afterward. If heartburn is constant, see Acid Reflux and Canker Sores.

Tender, bleeding gums. Pregnancy gingivitis is common because hormones make gum tissue swell and bleed more easily. Brushing harder to fix it makes things worse. A soft brush is gentler on both your gums and any sores; see Gingivitis and Canker Sores.

Toothpaste. If you haven't already switched, an SLS-free toothpaste is one of the cheapest changes with evidence behind it. Sodium lauryl sulfate, the foaming agent in most toothpastes, is linked to more frequent canker sores in some people. See SLS-Free Toothpaste for Canker Sores.

Sleep and stress. Both get harder in pregnancy and much harder after the birth. Both are linked to outbreaks; see Sleep and Canker Sores and Stress and Canker Sores.

Why Many Women Get Fewer Sores While Pregnant

Pregnancy asks the immune system to tolerate a baby that carries the father's genes, which the body would normally treat as foreign. To make that work, the immune system shifts away from "Th1" activity, the cell-killing kind, toward "Th2" activity, which is more about tolerance and antibodies. Progesterone, HCG and other pregnancy hormones drive the shift.

That matters for canker sores because the sores are caused by cell-killing T-cells attacking the lining of the mouth, which is a Th1-type process. When pregnancy turns Th1 activity down, it makes sense that sores would become less frequent. Many women with recurring canker sores do say they get fewer while pregnant. But the research is thin: a review of hormones and canker sores found that a link with pregnancy hadn't been established by well-designed studies (McCartan & Sullivan, 1992 — PMID: 1495706). So the immune shift is a reasonable explanation for a common experience, not a proven one.

Why some women get worse

Not everyone improves. The immune changes of pregnancy aren't a simple dial turned down; some parts of the immune system become more active at the same time, and the balance varies from person to person. The first trimester, when hormone levels are climbing fast and haven't settled, is when some women notice more sores before things calm down later. If your sores haven't let up, that's not unusual, and it's worth mentioning to your OB. It's also a good reason to ask for the blood tests in the nutrition section above. See Canker Sores During Your Period for more on how hormone swings affect outbreaks.

If you are getting fewer sores, don't assume they're gone for good. Fewer sores while pregnant isn't a cure.

After the Birth: Be Ready

After delivery, progesterone and HCG fall sharply within days as the placenta is delivered. Whatever calming effect pregnancy had on your immune system lifts. Women who had fewer sores during pregnancy often report that outbreaks come back in the weeks after the birth, sometimes worse than before. This comes from clinical experience and women's reports rather than formal studies, but it's common enough to plan for, especially since it lands in the newborn weeks, when sleep is short and you have the least time to deal with anything else.

Before your due date:

• Stock barrier patches and a numbing gel so you're not running to the pharmacy with a newborn.
• Keep your SLS-free toothpaste and soft brush going. Small habits are the first to slip after a birth.
• Keep taking your prenatal if your OB recommends it while breastfeeding, and recheck iron, since blood loss at delivery can lower it further.
• Know which dentist you'd call for a severe sore, so a bad one gets seen quickly. See When to See a Doctor for a Canker Sore.
• Expect it to settle as your hormones even out. Breastfeeding can stretch out the hormonal changes, and women report mixed effects on their sores.

A simple kit to have on hand:

For getting through a sore quickly once it shows up, see The Fastest Way to Heal a Canker Sore.