Oral administration is the most common form of drug administration. The appropriate dosage form (tablet dragée, capsule) is relatively easy to prepare and easy and convenient to administer. The advantage is the problem-free admission and thus the possibility of self-administration by the patient, which is a largely indispensable prerequisite, especially for long-term therapy. Restrictions of oral application arise in cases of urgency (vital indication), unconscious patients, patients sensitive to the gastrointestinal tract and non-cooperative patients (e.g. risk of overdosage or underdosage) and insufficiently absorbable oral substances.