Poison gas was gas containing toxic properties. When Qui-Gon Jinn and Obi-Wan Kenobi boarded the Neimoidian flagship Saak'ak to try to end the blockade of Naboo, the Sith Lord Darth Sidious demanded that the Neimoidians execute them and the Neimoidians tried to do so with dioxis, but were unsuccessful.
- Star Wars: Episode I The Phantom Menace (First appearance)
- Star Wars: The Clone Wars – "The Zillo Beast Strikes Back" (First identified as Poison gas)
- Star Wars: The Clone Wars – "The Box"
- Star Wars: Episode VII The Force Awakens (Mentioned only)
- Star Wars: The Force Awakens novelization (Mentioned only)
- The Force Awakens, Part II (Mentioned only)