The techniques of in vivo tissue fluorescence photometry and chemical extractions of DHE, which have been recently developed in our laboratory, were employed to study DHE uptake and clearance in the primate bladders. Data show these techniques are readily applicable in studying porphyrin uptake and clearance in primate bladders. Quantitatively a correlation between fluorescence values and tissue extracted DHE values is found. Serum clearance and bladder clearance of DHE appeared phasic, but bladder clearance was slower than serum. The significance of these two methods lies in their applications in determination of drug dosimetry and optimum time for photoactivation in clinical photodynamic therapy.