In one episode Beavis goes to prison and he is seen smoking a cigarette with his cellmate. Beavis is also seen unsuccessfully trying to light up a cigarette or a joint in some other episodes during the music video sequences.
The character Principal McVicker is a corrupt and unstable alcoholic, that drinks even on his job to numb his stress. He stutters like "uhh ... what are doing?"He shakes really bad in all the episodes he is in, this shows he is an alcoholic.
From the end of Season 4 as a running gag, when Beavis consumes stimulants (sugar, coffee, pills etc.) he becomes hyperactive and starts speaking gibberish, then pulls his shirt collar over his head and becomes The Great Cornholio, his Spanish alter ego.
Contains some occasional smoking and drinking throughout the course of the series, though Beavis and Butt-head are seldom seen indulging in such acts, however, Beavis and Butt-head consider the use of drugs and alcohol to be "cool", though the series as a whole does not promote the use of such substances as it largely serves as a commentary on self-destructive, uneducated, misanthropic youth.
In a controversial episode which is no longer available in circulation, Beavis and Butt-head swallow condoms full of drugs with the intention of smuggling them.