The Effect of Viola odorata Flower Syrup on the Cough of Children With Asthma

This study aimed to investigate the effect of violet syrup on cough alleviation in children with intermittent asthma. In a parallel, double-blind, randomized controlled trial, 182 children aged 2 to 12 years with intermittent asthma were randomly assigned 1:1 to receive violet syrup or placebo along with the common standard treatments in both groups (short-acting β-agonist). Both groups were evaluated in terms of the duration until cough suppression was achieved. No significant difference was observed in basic characteristics. The duration lasting to yield more than 50% cough reduction and 100% cough suppression was significantly less in the violet syrup group compared to placebo (P = .001, P < .001, respectively). There was no significant difference in therapeutic effects between boys and girls. There was a significant inverse correlation between the age of children and rate of cough alleviation and suppression by violet syrup. This study showed that the adjuvant use of violet syrup with short-acting β-agonist can enhance the cough suppression in children with intermittent asthma.