Actually, it might not even get through FDA tests at all if introduced today. I work for a metabolomics researcher, which is the study of what happens chemically at the cellular level in various circumstances (e.g. while a cancer cell is dying). He said that while they have a theory about how aspirin works (at the cell level), no one knows for sure.

We also had an interesting talk the other day about caffeine and nicotine. Both are alkyloids, used by the plants to ward off disease and insects. So, we are getting high off smoking and ingesting insect repellant and anti-fungals.