Background: Bronchial asthma in adults is typified by lingering allergic inflammation associated with elevation in the levels of certain acute phase reactants and indicators of mast cell activation. This study investigated the effect of corticosteroid treatment on the levels of C reactive protein (CRP), serum baseline tryptase (sBT), erythrocyte sedimentation rate (ESR) and granulocyte monocyte colony stimulating factor (GM-CSF) among asthmatics. Method: Forty five adult patients with bronchial asthma on treatment with inhaled corticosteroids were enrolled. Forty five blood donors were used as control. Serum levels of CRP, sBT, ESR and GM-CSF were measured using sandwich ELISA. Result: The GM-CSF, CRP, ESR and sBT were significantly elevated among asthmatics on treatment compared to normal healthy control. Significant difference in the level of GM-CSF, ESR and CRP was observed between asthmatics with mild and moderate disease severity. Conclusion: Treatment with inhaled corticosteroids does not restore the levels of GM-CSF, CRP, sBT and ESR to normalcy among asthmatics.