The ability for a medical simulator to automatically recognize and respond to a "drug" injected during a training exercise offers powerful capabilities for objective assessment and real-time interaction. To address some of the limitations of available mannequin drug recognition systems, we developed a novel sensing system that recognizes an IV-injected agent based on an inherent property of the fluid. Our system uses varying concentrations of saline to represent different drugs and identification is made via conductivity measurement. The system also determines the volume administered and the time over which the dose is injected. Simulant solutions in IV bags (e.g., simulated Hextend or crystalloids) can be identified even if the bag is placed at a distance from the body. The system may offer advantages for field training exercises, as no external components need to be attached to the syringe or IV bag.