Royal Jelly produced by a Queen or Queen Mother was believed to be involved in the creation of new Queens, similar to the way terrestrial bees and other eusocial insects create fertile queens. Royal Jelly could be used to create Praetorians from Drones if the situation called for it. If the Queen died and there were no Praetorians to take her place, the Royal Jelly could be a last resort to creating a new Queen. Its exact purpose is unknown, however.
The Jelly is unique to every Queen, making each Hive different. It is also extremely addictive to humans if used as a drug, offering its users a euphoric sense of bliss and wonder. However, too much exposure to Royal Jelly can lead to heavy mutation, as was the case with Prof. Kleist's Bug-Men.
In the aftermath of Earth's infestation in the late 22nd century, humans harvested Royal Jelly from the remaining Xenomorph Hives, where it was refined and marketed as the performance-enhancing drug Xeno-Zip by the Grant Corporation. Known on the street as "Fire", the drug also contained a minuscule amount of Royal Jelly recovered from the remains of the Queen Mother destroyed on Earth. Less potent synthetic versions were manufactured as supplies of the pure substance dwindled, and therefore the United States Colonial Marine Corps mounted a recovery operation to Xenomorph Prime for more.
The Xenomorph drone Ol' Blue was used by authorities to search out junkies and drug dealers selling Royal Jelly. Since Blue was from a different Hive than that of the Jelly drug being sold on the street, Blue furiously hunted for the scent of the Jelly as if sensing another opposing Hive.
- The concept of Xenomorph-produced 'royal jelly' is first mentioned by Bishop in Alan Dean Foster's novelization of Aliens.
- In the 2010 video game Aliens vs. Predator, canisters of Royal Jelly serve as the collectible item of the Alien campaign. Once the player has found and smashed all of the canisters, they will unlock the trophy/achievement "Quite a Specimen".
- Some have theorized that it was close contact with Royal Jelly, as a result of destroying these canisters, that caused Specimen 6 to turn into a Queen.
- The black liquid has a similar effect on organisms as Royal Jelly, only the effects are more acute.
- Aliens (novel) (mentioned only)
- Aliens: Genocide/novel
- Aliens: Harvest/novel
- Aliens: Colonial Marines (comic)
- Aliens: Cargo (mentioned only)
- Aliens: Music of the Spears/novel
- Aliens vs. Predator (video game)
- Alien: River of Pain (indirect mention)