Evaluation of efficacy of combination of nebulized salbutamol with different concentration of saline (normal saline 0/9%, hypertonic saline 3%) in infant with bronchiolitis whom admitted in Ali Ebne Ab iTaleb hospital of Zahedan, Iran. Design: randomized, double blind, without control with placebo, unicentral, stage 3 of clinical trial on infant with bronchiolitis whom admitted in hospital (age 4 weeks up to 24 months) and require oxygen therapy. Inclusion criteria: age less than 2 year old; history of recent upper respiratory viral infection which caused wheeze and crackle in auscultation; CBSS 4-8 in admit. Exclusion criteria: age less than 1 month or more than 2 years old; history of recurrent attack of wheeze; sever neurological disorder; consolidation in Chest x ray; immune deficiency; congenital heart disease; history of premature (gestational age less than 34 weeks); birth weight less than 2500 gr; saturation of oxygen less than 85% in room; CBSS less than 4 or more than 8; unstable hemodynamic (heart rate more than 200 per minute,blood pressure 2 standard deviation more or less than normal range for age and sex, respiratory rate more than 70 per minute). Sample size:180; infants who have inclusion criteria and their respiratory rate is between 30-60 (moderate group) with method of random number table divided in 3 groups, each group has 60 person.group 1 receive 5 ml normal saline 0/9 % and 0/15 mg/kg nebulized salbutamol, group 2 receive 5 ml hypertonic saline 3% and 0/15 mg/kg nebulized salbutamol, group 3 receive 10 ml normal saline 0/9 % and 0/15 mg/kg nebulized saline, then clinical features, oxygen saturation, respiratory rate, heart rate, intercostal retraction, dyspnea and wheezing evaluated pretreatment and each 30 minutes after treatment up to 3 times.