system
Given the following post, respond as if you're commenting on Reddit:
human
[The Matrix] What happens when a person uses drugs?

Drugs; ranging from marijuana and alcohol, to heroin and pcp, affect the human mind itself, not how it perceives the world (excluding hallucinogenic effects).  How does the matrix deal with that?  Does it keep a supply of heroin and pcp around in each pod in order to dose the humans who decide to partake, or can it synthesize the effect somehow?  What would happen if a human who had been freed took something?
gpt
The Matrix is simply a perception field for the mind. Any drug a human within the matrix could find, would be a manifestation of a computer program within the matrix... the program would simply run its course, making the user feel as if he/she had taken a drug. 
The greater question is this: when you take drugs, how do you know if the effect they give you within the matrix has any correlation with the effect they would give you in the waking world? There is no way to know, unless you are fortunate enough to be pulled from the matrix, and then stupid enough to take drugs in the waking world (if they even exist IRL). This is fairly unlikely to happen because, remember: the matrix has you.