Why do drugs have oral and external use?

Internal use mainly depends on digestion and absorption, and external use mainly depends on infiltration and absorption of skin cells, with different positions and speeds.

Generally speaking, there are labels on the outer packaging, and there are instructions for usage and dosage. The doctor will tell you how to take the medicine.

For example: 1. Generally, there is a small box in the upper right corner of the medicine packaging box for external use, which says "external use".

There are four small words at the bottom: "external medicine"

2, all drugs must have "usage and dosage" on the outer packaging box, and after this.

The first thing to do is to introduce how to use it. Generally speaking, the word "oral" is an indication for internal medicine; external use/application

Generally indicate the word "external use".