Our recent research has shown that skin becomes temporarily transparent when a hyper-osmotic agent such as glycerol is introduced into the tissue. Local dehydration and index matching reduce light scattering which increases the penetration depth of collimated light. We have shown that when glycerol is applied to in vivo hamster skin, the resulting transparency is sufficient to allow visualization of blood vessels, and there is a temporary reduction in local blood flow. The reduced blood flow combined with greater light delivery significantly reduces the laser fluence rate [W/cm 2 ] required to coagulate dermal blood vessels.