||The cutaneous microcirculation is a desirable model for pharmacologic and physiologic studies of inflammatory mediators. For exact measurements of the induced blood flow changes, two objective methods are introduced. The laser-Doppler flowmeter and the 133Xe washout technique have formerly been used for measurement of the undisturbed cutaneous blood flow. We have modified these methods to measure changes in the blood flow following intracutaneous deposition of a vasodilator, leukotriene D4. When compared with a metric estimate of the erythemal response, the two new methods were found to be more sensitive than the traditional estimate of cutaneous blood flow changes. Both methods exhibited a good sensitivity and reproducibility when applied simultaneously, although the 133Xe washout technique appeared to be able to separate interindividual differences that could not be recognized by the laser-Doppler technique. Even though the laser-Doppler technique is superior in simplicity of use, the 133Xe washout technique is recommended for exact measurements.