A previous study conducted by our group demonstrated that Radix Astragali compounded with Codonopsis pilosula and Plastrum testudinis was effective in treating pediatric beta-thalassemia in a randomized, controlled clinical trial. However, the mechanism of action that underpins this treatment remains to be elucidated. Blood was collected from patients participating in this clinical trial and nucleated red blood cell-enriched mononuclear cells were isolated to facilitate the extraction of RNA and protein. RT-PCR was used to monitor the expression of globin genes and p38 MAPK, and total and phosphorylated p38 MAPK expression was assessed using Western blot analysis. Expression of alpha-, beta-, and A gamma-globin mRNAs was not significantly affected following treatment with R. Astragali or the compounded formulation. However, G gamma-globin mRNA levels increased significantly in both treatment groups (when compared with pretreatment levels) following 12 weeks of treatment. Moreover, posttreatment G gamma-globin expression was significantly higher in both treatment groups compared with the control group. Although neither p38 MAPK mRNA nor protein levels were affected by the treatments, posttreatment phosphorylation of p38 MAPK was significantly increased in the R. Astragali and compounded formulation groups compared with the control group. These data suggest that the molecular mechanisms that underpin the efficacious use of R. Astragali (and its compounded formulation) in pediatric beta-thalassemia treatment facilitate the induction of G gamma-globin expression following activation of p38 MAPK.