Here's the exact list of them all FYI.

I borrowed this from
http://www.signonsandiego.com/news/mexico/20060428-1857-mexico-drugs....

Allowable drugs

List of maximum allowable drug quantities approved for personal use by
Mexico's Congress:

 Opium (raw, to be smoked) 5 grams
 Heroin, 25 milligrams
 Marijuana 5 grams
 Cocaine 500 milligrams
 LSD .015 milligrams
 MDA 200 milligrams
 MDMA (ecstasy) 200 milligrams
 Mescaline: 1 gram
 Peyote: 1 kilogram
 Psilocybin (concentrate, pure, active ingredient) 100 milligrams
 Hallucinogenic mushrooms (raw, off the farm): 250 milligrams
 Amphetamines: 100 milligrams
 Dexamphetamines: 40 milligrams
 Phencyclidine (PCP, or Angel Dust) 7 milligrams
 Methamphetamines: 200 milligrams
 Nalbuphine (synthetic opiate): 10 milligrams

Now even an alien can have a nice party on all that.
:)