Common Sense Note
Parents need to know that this very addictive series is all about terrorism. The violence is relentless, albeit usually somewhat bloodless (with the notable exception of some gory torture scenes), and the lead character is rarely remorseful for anything he does in the name of duty/accomplishing his goals. Villains are sometimes portrayed stereotypically, although, in general, the show depicts women and minorities without bias. Discussion of sex is common, but not a major plot element. Because 24 is expressly designed to be addictive, parents not wanting their teens to watch every episode shoud probably avoid letting them them get started at all.
Fairly infrequent sexual references/activity, though characters (mostly women) do end up scantily clad in some scenes, and sex (whether for pleasure or as an act of manipulation) is sometimes implied via bedroom scenes.
Intense violence -- torture, gunplay, stabbing, poisoning, explosions, plane/car crashes -- sometimes with blood.
Very frequent use of "dammit" by Jack; other words include "hell" and "bitch."
While Jack and his allies always seem to end up accomplishing their goals -- save the president/country/world -- they do so through very iffy means, including torture, deception, and much more. All of this sends a strong message that the "right" ends can justify the means, no matter what those means might be. The show also clearly takes the perspective that it's worth sacrificing almost anything for the greater good and places a strong emphasis on duty and loyalty.
FOX News plays a major role in the show. The Sprint logo is visible on constantly-in-use cell phones, and many vehicles are product placements as well.
Drugs / Tobacco /
Jack used to use heroin but talks about it with regret. Minor characters drink and smoke.