No actual sex or nudity is shown, but Porgy and Bess clearly live together out of wedlock and are lovers. At the end of each of their big duets, "Bess You Is My Woman Now" and "I Loves You Porgy", they kiss passionately, with Porgy kissing Bess on the neck as well as on the lips.
Crown and Bess are former live-in lovers; Bess is a former prostitute and Crown is her pimp.
Violence & Gore
Mild
There are two important fights, and each one of them leads to a murder.
Profanity
None
None. The word "damn" has been omitted from the screenplay, and no serious profanity could be used in a 1959 Hollywood film, so the word "bastard" has also been eliminated.
Alcohol, Drugs & Smoking
Mild
Crown, the main villain of the story, gets so drunk during the crap game that he starts to think others are cheating when they are not.
Frightening & Intense Scenes
Mild
The two fights mentioned above; there is also a hurricane scene. Neither scene is truly frightening, however.