Syringes are the weapon of choice of Dr. Schabbs, who throws them at the player as projectiles. The syringe is stated to be filled with "Corpso-kinetic Serum" ("Corpse-moving serum", also spelled "Korpsokinetic Serum"needs verification). This serum was used by Dr. Schabbs in the Atari Jaguar port of Wolfenstein 3D to create mutants.
In the original MS-DOS version, it turns the player into a mutant upon death from syringes. In the Mac Family, the syringes are simply explosive (like Nitroglycerine).