How do drugs know where to go in the body? A pharmaceutical scientist explains why some medications are swallowed while others are injected
- Written by Tom Anchordoquy, Professor of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus

When you take aspirin for a headache, how does the aspirin know to travel to your head and alleviate the pain?
The short answer is, it doesn’t: Molecules can’t transport themselves...