From the Manufacturer:
Taurine is a crystalline, free-form amino acid. It is a soothing, inhibitory neurotransmitter, and plays a major role in stabilizing the heartbeat and electrical activity of the nerves. Taurine is also neccessary for the proper functioning of the "sodium/potassium ATP-ase pump" which regulates the ion balance between the cells and the extracellular fluid that surrounds them. This critically important "pump" actually uses 7% to 40% of the ATP energy our bodies produce.