The effects of micelles on the fluorescence detection of phenolic compounds are described. Micelles were found to enhance the fluorescence of the drugs apomorphine (APO), and N-n-propylnorapomorphine (NPA), and a series of model hydroxybiphenyls. The fluorescence enhancements were pH dependent and biphasic behavior in hexadecyltrimethylamnonium chloride was observed for APO and NPA. Multiple equilibria and formation of zwitterions of the phenolic aporphines in the micellar environment is proposed to explain this behavior. Micellar fluorescent enhancements should be useful in improving the sensitivity of fluorometric determinations of polar compounds.