The goal of this randomized clinical trial is to to compare the effect of topical rebamipide to topical betamethasone on oral ulcer severity in patients with Behcet's disease.. The main question it aims to answer is :

What is the effect of topical Rebamipide mouthwash compared to topical betamethasone mouthwash in management of oral ulcers in Behcet's disease?

Participants will will be divided randomly into the two groups and the following outcomes will be measured:

The oral ulcers severity Pain associated with oral ulcers Number of oral ulcers Healing time of oral ulcers

This is a Randomized clinical trial (RCT) parallel groups, two arm, equivalence framework with 1:1 allocation ratio which is based on the hypothesis that Topical rebamipide has comparable effect to topical betamethasone on oral ulcer severity in patients with Behcet's disease The participants in this study will be recruited from the Rheumtology Clinic, Kasr el ainy hospital by HL as well as Oral Medicine Clinic and the dental Diagnostic center, Faculty of Dentistry, by MB. The eligible participants will be enrolled in the study in a consecutive order till the sample size is achieved.

Simple randomization will be generated using computerized random number generator (random.org) with allocation ratio (1:1).

Allocation concealment will be done using sequentially numbered opaque sealed opaque containers of the same shape, size and colour until interventions are assigned.

The entire procedure will be explained to the patients and a written consent will be obtained by the operator.

Participants and care givers will be blinded as both topical rebamipide and topical betamethasone mouthwashes will be of same consistency and will be provided in sealed opaque containers of the same shape, size and colour.

The enrolled patients will be divided randomly into two groups. One group will receive topical rebamipide mouthwash four times daily for one week or till healing and the other group will receive topical Corticosteroid (topical betamethasone) four times daily for one week or till healing. The patients will be recalled during the first week (days 1, 3, and 7), then every week for 3 weeks, afterward every month for 2 months. The patients will be asked to prohibit use of any topical medication during the trial. Outcome measures will be recorded in each visit.

Data will be analyzed using IBM SPSS advanced statistics (Statistical Package for Social Sciences), version 24 (SPSS Inc., Chicago, IL)

Inclusion Criteria:

1. Patients diagnosed with Behcet's disease as defined by the revised International Criteria for Behcet's Disease (ICBD2014).
2. Patients with active oral ulcers.
3. Patients free from any visible oral lesions other than the oral ulcers of BD.
4. Patient who will agree to participate in the study and take the supplied interventions.

Exclusion Criteria:

1. Patients with history of a severe or chronic medical condition including congestive heart failure, malignancy and active infection including tuberculosis, hepatitis and human immunodeficiency virus.
2. Patients who refuse to sign the informed consent.

the allocation of the participants to the groups will be concealed . The bottles of both mouthwashes will be the same. The solution of both mouthwashes will be of the same colour, odor and consistency.