The aim this study was to investigate the efficacy of Er,Cr:YSGG laser irradiation in reducing pain and on healing rate of recurrent aphthous stomatitis 40 patients with RAS were included to the study. For each patient, ulceration were randomly assigned to the test or the control group. In test group RAS irradiated with Er,Cr:YSGG laser using non-contact mode. In the placebo group, the same Er,Cr:YSGG laser without laser emission was used. Pain was evaluated with visual analog scale (VAS). Healing of RAS (HRAS) was graded by a clinician.

Inclusion Criteria:

• For inclusion every patient had to have one pairs of minor RAS duration of 3 days or less, in the buccal or labial nonkeratinized oral mucosa.

Exclusion Criteria:

• Patients with a known systemic disease that predisposed them to RAS (e.g., Behçet disease), presence of any major herpetic lesions, traumatic ulcers, ulcers caused due to topical or systemic medications, or undergoing systemic or local treatment for RAS were excluded.