Problem analysis: Generally speaking, taking medicine before meals is mainly to take medicine 30 minutes before meals, and taking medicine after meals is to take medicine 15-3 minutes after meals.

Opinions and suggestions: Taking medicine before meals can avoid first-pass elimination and maximize drug absorption. Taking medicine after meals is mainly to avoid gastrointestinal side effects, but first-pass elimination will reduce drug absorption. The Lingbei cough syrup you mentioned can be taken before meals.