BACKGROUND AND OBJECTIVE: After Iron, zinc is the second most abundant trace element in the body that is present in all organs, tissues and body fluids. It is a necessary component for maintaining immunological integrity antioxidant activity, and has critical role in the control and prevention of infection. The aim of this study was to investigate the effect of zinc sulphate syrup in treatment of children with respiratory tract infection. METHODS: In this randomized clinical trial study, one hundred and twenty four children with respiratory infection (62 in case and 62 in control group) from pediatric ward of Hajar hospital of Sharekord university enrolled. Both groups received standard treatment. In addition to, zinc sulphate syrup was given to case group and placebo to control group. Respiratory rate, bed and cough and fever duration were compared between the case and control groups (IRCT: 201103025951N1). FINDINGS: The mean duration of fever in the case group was 2.6±0.82 days and in the control group 4±1.5 days (p<0.001). The mean of bed duration in the case group was 4.7±1.5 days and in the control group 5±1.8 days (p=0.42). The mean of cough duration in the case and control groups was 3.4±1.3 and 4.7±1.6 days respectively (p=0.09). Respiratory rate in the case group was 28.3±4.3 and in the control 28.1±4.9 (p=0.77). CONCLUSION: The study showed that zinc supplementation has a beneficial effect in decreasing the fever duration in children with respiratory infection. But there was no significant effect on respiratory rate, duration of bed and cough
