approximately five pounds of it. trillions of microbes trillions of bacteria approximately five pounds of it. 100 trillion good bacteria call human body home - SFGate about 100 trillion bacteria 100 trillion good bacteria call human body home - SFGate one hundred trillion bacteria 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate trillions of bacteria 100 trillion good bacteria call human body home - SFGate http://www.sfgate.com 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate approximately five pounds of it. 100 trillion good bacteria call human body home 100 trillion good bacteria call human body home - SFGate approximately five pounds of it. 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate approximately five pounds of it. 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate approximately five pounds of it. 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate approximately five pounds of it. 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate approximately five pounds of it. approximately five pounds of it. approximately five pounds of it. Allday 100 trillion good bacteria call human body home 100 trillion good bacteria call human body home - SFGate over a trillion organisms 100 trillion good bacteria call human body home - SFGate via trillions of bacteria 100 trillion good bacteria call human body home - SFGate 100 trillion good bacteria call human body home - SFGate