The Chimera possess amazing metabolic rates that enable them to heal from injuries very quickly; however, their healing abilities are further complimented by use of an artificial bacteria which amplifies their ability to regenerate significantly. The bacteria are suspended in a yellow liquid called the Sym-Bac serum, which is in turn found in small cylinders for storage. The bacteria are destroyed during the healing process, requiring further injections of the substance if more damage is sustained.
In Resistance: Retribution, it was confirmed that humans can also use Sym-Bacs to recover from injuries, as James Grayson was able to use them to restore his health. In one cutscene, he is clearly shown giving a canister of Sym-Bac to a wounded Maquis soldier. Unlike in the other games, in Retribution Sym-Bacs appear with a red color.
- According to Raine Bouchard, Chimeran Dropships are used to scatter Sym-Bacs on the battlefield for injured Hybrids. She also mentions that they work on humans as well.