Mouth Ulcers in Kids: Causes, Home Remedies & When to See a Dentist

"Doctor, my child is refusing food and crying while eating." Nine times out of ten in my Bharuch clinic, it is a mouth ulcer. Mouth ulcers in kids are common, painful and almost always harmless — but knowing the cause, the safe home treatment and the red flags saves your child days of misery.

What is a mouth ulcer?

A mouth ulcer (aphthous ulcer or canker sore) is a small round or oval sore with a white-yellow centre and a red border. In children they appear on the inner cheek, tongue, inner lip or the floor of the mouth. Most heal on their own in 7 to 14 days without scarring.

Why do kids get mouth ulcers? Common causes

• Accidental bite or injury — biting the cheek, a hard toothbrush, a sharp broken tooth or braces wire
• Hot food burn — chai, hot milk, fresh roti straight off the tawa
• Vitamin B12, iron or folate deficiency — very common in Indian children and the top cause of recurring ulcers
• Viral infections — hand-foot-and-mouth disease, herpetic gingivostomatitis (multiple ulcers plus fever)
• Stress and exam pressure in school-going kids
• Acidic and spicy foods — citrus, tomato, chips, masala snacks
• Sodium lauryl sulphate (SLS) in some toothpastes
• Constipation and dehydration — the classic "pet garmi" pattern parents describe

Mouth ulcer home treatment for children

1. Cold relief first — ice chips, chilled milk, curd, kulfi or plain vanilla ice cream numb the sore and keep calories going in.
2. Salt-water rinse — half a teaspoon of salt in a glass of warm water, twice a day, for children old enough to spit (usually 5+).
3. Honey dab — a small amount of honey directly on the ulcer is soothing and mildly antibacterial (only above 12 months).
4. Coconut oil or ghee — a thin coating reduces friction while eating.
5. Soft, bland diet — khichdi, dal-rice, curd-rice, banana, mashed potato. Avoid citrus, tomato, chips and spicy food until it heals.
6. Switch to an SLS-free, soft-bristle brush routine and keep brushing — stopping brushing makes it worse.
7. Paediatric oral gel only if prescribed. Avoid adult ulcer gels with high benzocaine in young children.

What about vitamin deficiency?

If your child gets ulcers more than 3–4 times a year, don't just treat the sore — treat the cause. Ask your paediatrician for a haemoglobin, serum iron, vitamin B12 and folate check. In our experience in Gujarat, correcting a B12 or iron deficiency stops recurring ulcers in most children within 8–12 weeks.

Foods that help vs. foods that hurt

• Help: curd, milk, banana, coconut water, khichdi, paneer, cooked vegetables, plenty of water
• Hurt: lemon, orange, tomato, pickle, chips, kurkure, masala noodles, very hot food, hard toast

When to see a dentist or doctor

Book an appointment if you notice any of these:

• Ulcer lasting more than 2 weeks
• Ulcers that keep coming back every few weeks
• Very large ulcers (bigger than 1 cm) or unusually deep ones
• Fever, multiple ulcers all over the mouth, swollen bleeding gums
• Child refusing all food and fluids, or showing signs of dehydration
• An ulcer next to a sharp broken tooth, a decayed tooth or a braces wire — the cause must be fixed or it will return

At Little Angels Kids Dental Care in Bharuch, we smooth sharp teeth or brackets, treat any underlying decay and give a child-safe pain plan the same day. If your child has tooth pain at night along with the ulcer, that usually points to decay that needs attention.