Leukotriene Receptor Antagonists or Steroids in Pre-School Asthma

Inclusion Criteria: * Male or female patients age 4 -6 years * Diagnosis of mild intermittent bronchial asthma (Step I-II) in the past 6 - 12 months as stated by the investigator: * Use of inhaled beta-2-agonists \< 1/week (max 3 puff /d) * Exacerbation-free interval \> 4 weeks prior to visit 1 * The written informed consent of parents after received written and oral information about the aim, purpose and risks of the study must be present Exclusion Criteria: * Asthma severity ≥ Step 2 * Severe concomitant diseases * Suspected non-compliance * age below 4 and age above 7 years * last study participation \< 30 days