Which route of administration involves the mouth, stomach, and intestines?

The correct answer is the oral route of administration. This method involves the ingestion of medications through the mouth, allowing them to pass through the stomach and intestines before being absorbed into the bloodstream. The oral route is one of the most common and convenient ways to administer drugs, as it allows for easy self-administration and is generally well-accepted by patients.

The oral route also provides a slower onset of action compared to some other routes, as the medication must be dissolved and absorbed in the gastrointestinal tract, which can be beneficial for certain therapeutic effects.

In contrast, while the mouth is involved in the process of taking medication, it does not encompass the entire route through the stomach and intestines. The buccal route involves placing the medication between the gum and the inner lining of the cheek, allowing it to dissolve and be absorbed directly into the bloodstream, bypassing the gastrointestinal tract entirely. Subcutaneous administration refers to injecting under the skin, which does not involve the gastrointestinal system at all. Thus, the oral route is the most accurate choice as it explicitly describes the entire path from ingestion through the digestive system.