To test whether simvastatin has an additional anti-inflammatory effects on p38 MAPK, a signaling molecule for inflammation in inhaled steroid-treated asthmatics.

Inclusion Criteria:

• mild-to-moderate persistent asthmatics
• FEV1 = OR > 50% of predicted

Exclusion Criteria:

• Previous history of renal disease or serum creatinine is more than 2 mg/dl.
• Previous history of liver disease.
• Pregnancy or lactation.
• Are already receiving or are known to be allergic to statins or to have developed myositis.
• Have an asthma exacerbation requiring treatment with oral corticosteroids during the 3 months prior to the commencement of study entry.
• Being treated with immunosuppressive agents.
• Unwilling to cooperate the study.