The recommended time for taking montelukast varies depending on the condition it is being used to treat. When montelukast is used to treat exercise-induced asthma, it is recommended that you take it at least two hours before exercising (and not within 24 hours of a previous dose). This can be at any time throughout the day. When montelukast is used to treat asthma, it is recommended that you take it in the evening. The FDA says that although there is no evidence that montelukast is more effective when taken in the evening than in the morning, trials demonstrating its efficacy have all been conducted with evening doses. Basically, the advice for taking montelukast in the evening is due to a lack of evidence that it is effective when taken in the morning. When montelukast is used to treat allergic rhinitis, it is usually recommended that it is taken at the same time each day. However, this can be at any time during the day. In any case, montelukast can be taken without regard to when you eat. If you have any questions or concerns regarding the time at which you or your child takes montelukast, you should speak to your doctor.