IRCT20131217015835N7 IRCT 2018-05-17 Chancellor of Research and Technology, Zanjan University of Medical Sciences (Primary sponsor) Comparison of the effect of Zinc and Vitamin D supplementation on Acute Bronchiolitis Comparison of the effect of Zinc and Vitamin D supplementation on Acute Bronchiolitis in 2 to 23 months old children, a clinical trial 2017-09-27 anticipated 135 Complete https://irct.ir/trial/14985 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Simple and individual randomization is chosen. Random number table is used. We will use numbers from 1 to 135 in this table and we will read these numbers from up to down and we will write the succession. Then we will give Vitamin D to numbers 1 to 45 and Zinc to numbers 46 to 90 and no drugs to numbers 91 to 135. Then for allocation concealment we will use sequentially numbered, sealed, opaque envelopes. Every one who will enter our study will chose one envelope which has one number of the table in it and the group will be chosen for that person, Blinding description: In this trial participants and the outcome evaluators are blind. Participants know that they take supplements besides routine drugs but instead of the name of the supplements we use codes. The evaluators evaluate the outcomes according to the codes. N/A Acute bronchiolitis. Intervention 1: Intervention group: First group takes 2 mg/kg/day(max 20 mg) syrup Zinc Sulfate10 of Alhavy Company for 1 week or during hospitalization if the days of admission are less than 1 week. Intervention 2: Intervention group: Second group takes 100 unit per kg per day drop Vitamin D (1000 IU in 1 ml) of Vitabiotic company for 1 week or during hospitalization if the days of admission are less than 1 week. Intervention 3: Control group: Third group does not take any supplements. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is There is no more information.