BioShield™is powered by NeuroRX™. NeuroRX™was developed by pharmacists with Prescription Strength results... and is a proprietary formula of Portland Outdoors™. NeuroRX™works by attacking a neurotransmitter found only in insects. Neurotransmitters control the heart rate and metabolism. Fleas, ticks, mosquitoes and bed bugs produce a neurotransmitter called octopamine. NeuroRX™ blocks the octopamine, causing a complete shutdown of the central nervous system... killing insects nearly instantaneously. Octopamine is found only in insects. humans and other mammals, birds, and fish do not produce octopamine. NeuroRX™ is safe to use around children and pets but is deadly to insects when used as directed.