Since its inception, due to airing on the same channel space as Cartoon Network, Adult Swim opens with a Bump displaying a content warning regarding the nature of it's shows. Originally it started with a warning announcing that Adult Swim has "Potential Violence, Strong Language, and Adult Situations" while panning around a pool showing warning signs stating these things and other signs such as "Limited Animation". The announcer then ended it off saying "No Kids in the Pool, all Kids under 17 out, for Adult Swim". In later 2001, the disclaimer was made to be more formal, showing a detailed warning message on a black screen which the narrator reads word for word warning parents that the programs are intended for mature audiences over the age of 18 and that they contain intense violence, sexual situations, coarse language, and suggestive dialogue. That disclaimer was shown until May 22, 2003. The Action block on Saturdays in 2002 had a similar message but was announced by a computer robot voice.
On May 25, 2003, the warning was changed to reflect the rebrand of Adult Swim. It began with an image of the Parental Advisory logo as seen on the covers of Audio CDs and Cassette Tapes to alert parents that the music may not be suitable for young audiences. The intention is the same here, except "Explicit Lyrics" is replaced with "Mature Content". The bump then changes to a more specifically written message advising parents that the following programs may not be suitable for children. In August 2003, the message was changed a bit to say that the programs aren't suitable for viewers under the age of 14. In June 2006, Adult Swim added a slightly different message that showed during later hours of the block which said the programs weren't suitable for viewers under the age of 17. In May 2007, the Parental Advisory label was dropped and the message simply just states that Adult Swim may contain mature material that may not be suitable for some viewers. There is no age listed unlike before. This is the message that is shown to this day. The disclaimer typically appears at the beginning of every hour. The Parental Advisory logo was brought back in later 2008 only before the first show of the block and was again removed in May 2010 where they briefly showed the same disclaimer but with a picture of a brick wall in the background. This new variation of the disclaimer did not last very long. All of these disclaimers were silent.
Some shows also got their own specific disclaimers if they were deemed too violent. The episode "Jungle Cruise" of Ghost In The Shell: Stand Alone Complex, had a simple disclaimer stating that due to the nature and intensity of violence in the episode, Viewer discretion is Advised. Episode 51 of Fullmetal Alchemist premiered with a disclaimer stating "Just in case the last disclaimer wasn't enough, this episode contains extreme violence. We would rather run this than cut the violence from the episode because We are American Cowboys". This same disclaimer also aired before the premieres of Episode 26-52 of Eureka Seven, and the premiere of Episode 1 of Blood+. For subsequent airings of Blood+, a new disclaimer was introduced featuring a picture of a bomb in the background stating "This program contains scenes of intense graphic violence, Viewer discretion is Advised".
On March 31, 2014 with the expansion of the block to 8 PM, Adult Swim added content warnings with a time-lapse of a landscape in the background to go along with the addition of the new seasonal nature themed bumps. These new disclaimers even have music. They also use a different one for each day of the week. The disclaimer text is simply the same as the warnings that debuted in May 2007. These new disclaimers aired every hour for the first and last hours of the night, while from 11 PM until 5 AM, they aired the standard black & white text disclaimer that had been airing since 2007. In March 2017, the bump format was changed a bit and now the Time-Lapse disclaimers air at the beginning of each even hour and the standard black & white ones air at the beginning of each odd hour.
On every episode of Robot Chicken, it shows a message before the show stating that any actual names or likenesses of celebrities are used in a fictitious and parodic manner.