K12.0 — Recurrent oral aphthae

K12.0

ICD-10 Chapter 11: Digestive System — illustrative image — Chapter 11: Diseases of the digestive system (K00–K95) — illustrative image

What this code means

Recurrent oral aphthae are recurring mouth ulcers (canker sores) on the soft tissues inside the mouth.

Also called: mouth ulcers, aphthous ulcers, canker sores.

When this code is used

Used for recurrent oral aphthae.

Where it sits in ICD-10-CM

Code K12.0 belongs to Chapter 11: Diseases of the digestive system, which covers codes K00–K95 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.

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Frequently asked questions

What is ICD-10-CM code K12.0?

K12.0 is the ICD-10-CM diagnosis code for “Recurrent oral aphthae”. Recurrent oral aphthae are recurring mouth ulcers (canker sores) on the soft tissues inside the mouth.

When is code K12.0 used?

Used for recurrent oral aphthae. It belongs to Chapter 11 of ICD-10-CM (Diseases of the digestive system).

This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.