The application of host-modulating bacteria for therapeutic purposes is one of the strongest emerging fields. Probiotics are live microorganisms, which, when administered in an adequate amount, confer a health benefit on the host The study aimed to explore the effectiveness of probiotics in the treatment of the common ulcerative condition; minor recurrent aphthous stomatitis (RAS). We included sixty adult (group A) and 60 children patients (group B) with diagnosis of minor RAS . Both groups were divided into two subgroups, AI and BI (test subgroups ) and AII and BII (control subgroups). For test subgroups, probiotic lozenges were consecutively administered twice daily, for five days. The size and pain level of ulcers were recorded on treatment days 0, 3 and 5. The outbreak frequency of RAS within 6 months was investigated for all subgroups.

The study aimed to explore the effectiveness of probiotics in the treatment of minor recurrent aphthous stomatitis (RAS). We performed a randomized, controlled clinical study. Sixty adult (group A) and 60 children patients (group B) with diagnosis of minor RAS were included. Both groups were divided into two subgroups, AI and BI (test subgroups) and AII and BII (control subgroups). For test subgroups, probiotic lozenges were consecutively administered twice daily, for five days. The size and pain level of ulcers were recorded on treatment days 0, 3 and 5. The outbreak frequency of RAS within 6 months was investigated for all subgroups. Compared to baseline, an improvement was evident for all subgroups. However, for effectiveness in pain reduction, a statistically significant difference in favor of AI was observed for all evaluation periods when compared to control subgroup. Regarding effectiveness in ulcer size reduction, a statistically significant difference in favor of BI was observed at day 5 when compared to control subgroup. No significant difference was observed in the effectiveness index between subgroups AI and BI (test subgroups) except in effectiveness in pain reduction at day 3. The outbreak frequency decreased significantly in subgroup BI. We concluded that topical application of probiotics decreased pain intensity and accelerate RAS healing. The effectiveness in pain reduction is more evident in adult patients while acceleration of healing is more evident in children. Probiotics could be a well-tolerated, topical therapeutic agent in the treatment of minor RAS

Inclusion Criteria:

• Males and females aged 18-45 years old, 2. Patients presenting with RAS with the following characteristics: a. Minor aphthous ulcers less than 48 hours' duration prior to enrolment, b. Size no greater than 10 mm in diameter, c. A history that ulcers normally more than 5 days to resolve without treatment. The inclusion criteria for group B is the same except age, children with RAS aged between 3 and 12 years were recruited for the study.

Exclusion Criteria:

• A known history of hypersensitivities, immunologic or systemic diseases, pregnancy, smoking,
• treatment with systemic steroid or other immunomodulatory agents within 1 month before the study
• use of nonsteroidal anti-inflammatory drugs or oral antihistamines within 1 month prior to the study
• treatment of the ulcer with any preparation or medication within 72 hours prior to the study
• treatment with systemic antibiotics within 2 weeks prior to the study and a history of adverse reactions to lactose or fermented milk products.
• Children with a positive family history of RAS were excluded.

All clinical outcome variables are recorded by a single investigator whom is blinded to the treatment modalities