The capacity of bone tissue to alter its mass and structure in response to mechanical demands has long been recognized but the mechanisms involved remained poorly understood. Load-induced interstitial fluid flow has been postulated to provide a mechanism for transduction of the mechanical signals to the cellular level to activate bone adaptation. This research is to investigate experimentally the effects of mechanical loading on fluid flow in bone by introducing stain/tracer. Rat femurs were used to test the passive diffusion and mechanical transport properties of the stain in bone. It was found that fluorescein is compatible with an animal model and extensive stain transport occurs due to mechanical loading, and passive diffusion to a lesser degree. The stain transport increased with cyclic loading magnitude and frequency. It was also shown that extensive fluid transport at the canalicular level occurs rapidly within a few cycles of loading in rat femur.