BioShield for pets and livestock is a proprietary formula of Portland Outdoors and is powered by NeuroRx which was developed by pharmacists. NeuroRx works by attacking a neurotransmitter only found in inspects that control the heart rate and metabolism. Fleas, ticks, mosquitoes and bed bugs produce a neurotransmitter called octopamine. NeuroRx blocks the octopamine, causing a complete shut down of the central nervous system killing insects nearly instantaneously.