Women in low-cut dresses.

The Marx Brothers make (often unwanted) romantic advances towards women in the film; a women attempts to seduce them to get them in her room as a part of a scheme. No actual nudity or sex of any kind.

Slapstick, comedic fighting and the like. All of this is played for comedy and is not violent or gory in any way.

Nothing outside of childish name calling.

Social drinking and smoking, which was quite common at the time of the film's release.

None. The film always retains a light-hearted comedic tone.