The ablation of both soft and hard tissue using the normal-spiking-mode Er:YAG laser has been quantified by measuring the number of pulses needed to perforate a measured thickness of tissue. Bone is readily ablated by 2.94 microns radiation; however, at per pulse fluences greater than 20 J/cm2, plasma formation decreases ablation efficiency. At low fluence, desiccation can prevent efficient ablation of bone. The ablation efficiency for aorta and skin is higher than for bone. The ablation efficiency, 540 micrograms/J, and the ablation depth per pulse, greater than 400 microns, for skin are too high to be readily explained by simple models of ablation and thus provide evidence for a more complex explosive removal process.