Aim #1: To confirm that oral administration of silymarin in subjects with atopic asthma increases endogenous antioxidant enzymes. We hypothesize that silymarin will increase levels of antioxidant enzymes, superoxide dismutase activity, catalase activity, and glutathione peroxidase activity in subjects with atopic asthma. To test this hypothesis, we will first conduct a dose escalation study to determine optimal dosing, dose effect, and washout on airway inflammation, followed by a randomized, double-masked, placebo-controlled cross-over pilot investigation of supplementation with silymarin in subjects with atopic asthma with measurements of antioxidant enzyme activity pre-, during and at the completion of both active supplementation and placebo arms of the study.