Tobacco
Alcohol is the oldest drug known to man, and also the most widely-used drug. So, I would imagine it is the most widely-abused drug, as well.
This is more of a opinion type of question, but the general public would be against it as it's the world's most widely used (and abused) recreational drug, next to caffeine.
The most widely abused recreational drug is alcohol - by a substantial margin. The country with the highest per-capita alcohol consumption is probably Uganda. The most dangerous leisure drug is tobacco. Here Greece leads the way.
Marijuana is the second most widely used illegal drug in the US after cocaine.
Alcohol is the most used legal drug. Of Illicit drugs the most widely used drug is cannabis.
Marijuana.
oxycontin
Caffeine is the most widely used psychotropic drug in the world. It is found in coffee, tea, and many other beverages and foods.
Marijuana is definitely the most widely used illegal drug in the US. Marijuana is the most widely used illegal drug.
Smoking And Alchahol
Tobacco or alcohol :)