Asthma is characterized by airway inflammation that is controlled by a complex cytokine network. The Th1/Th2 imbalance has been well documented in the pathogenesis of allergic asthma. Recently, Th17 cells and regulatory T (Treg) cells have been found to participate in the pathogenesis of allergic asthma. This study aimed at verifying whether anti-inflammatory treatment could change serum IL-4, IL-10 and IL-23 in asthmatic children. Globally, 78 children (40 males and 38 females, median age 9.3 +- 3.7 years), with asthma and monosensitized to house dust mites, were evaluated. Lung function (such as FEV1) and serum IL-4, IL-10 and IL-23 levels were measured at baseline (T0), after 4 weeks (T1) and after 12 weeks (T2) of inhaled corticosteroid (ICS) treatment. The control group consisted of 40 healthy children (22 males and 18 females) age matched. At baseline, IL-4 and IL-23 levels were higher in severe asthmatics than in control group (p less than 0.001), while serum IL-10 levels were significantly lower in group of asthmatic children as compared to healthy control group (p less than 0.001). At T2, IL-4 and IL-23 significantly diminished (p less than 0.001), while IL-10 significantly increased. There was significant relationship between FEV1 and IL-4, IL-10 and IL-23 at T0 (r=-0.784; r=-0.735 and r=-0.787, respectively). Moreover, there were correlations between FEV1 and IL-4, IL-10 and IL-23 in patients at T1 (r=-0.563; r=-0.539 and r=-0.583, respectively) and at T2 (r=-0.549; r=-0.428 and r=-0.393, respectively). The present study provided evidence that: i) serum IL-23 was up-regulated also in asthmatic children, ii) ICS treatment was able of reducing IL-23, and iii) IL-23 change well related with lung function improvement. Thus, it is presumable that IL-23 could be a suitable marker of allergic inflammation in asthma.