The main findings of this meta-analysis are (1) patients with asthma had higher serum IL-6 concentrations than those in controls; (2) Serum IL-6 levels are elevated in both adult and pediatric asthmatics compared to controls, especially in pediatric asthmatics; (3) Serum IL-6 levels were higher in patients with exacerbation and stable asthma than in healthy non-asthmatic controls. Here, IL6 is linked to asthma.