Some sexual references.

Rape jokes occur in the later part of the series. Played for laughs, but might make some people uncomfortable.

A running gag is the two main characters being extremely neglient parents, often putting their baby in danger or even killing it sometimes.

Some punching and kicking.

In one scene, graphic violence is used, and blood spurts. However, it's not meant to be taken seriously.

Strong language throughout the series. Sometimes unbleeped, sometimes not.

Regular uses of fuck.

Occassional uses of hell, damn and shit.

A few uses of cunt.

Some beer drinking. One of the main characters tends to get drunk.

Infrequent drug use, such as in the opening for season 5.

There are some disturbing themes, but if you like dark comedy it shouldn't be a problem.