Quantification of the effect of subcutaneous infiltration of saline with epinephrine and of lidocaine with epinephrine on local cutaneous blood flow was accomplished utilizing the laser Doppler method. A comparison of the onset of vasoconstriction, magnitude of diminished blood flow, and duration of effect was made for several commonly used concentrations of epinephrine. Injected solutions containing epinephrine in concentrations of 1:200,000 and higher offered good vasoconstrictor effects when both the magnitude and duration of flow reduction were considered. There was a significant (P = 0.0001) difference in flow between epinephrine concentrations of 1:400,000 and all others. There were no significant differences (P greater than 0.05) between concentrations of 1:200,000 and 1:100,000 or 1:100,000 and 1:50,000.