AbstractThe occurrence of high amounts of dopa has been demonstrated chemically in the piliary system of pigmented animals (guinea‐pig, rabbit, and dog). Histochemically, a formaldehyde‐induced fluorescence was recorded only in melanocytes of hair‐bulbs. The spectral characterictics of these cells did not agree with those of the authentic dopa fluorophore. The discrepancy between the chemical and histochemical findings is discussed. Little or no dopa was found in non‐pigmented skin of albino and multi‐coloured guinea‐pigs. This indicates that the integumentary dopa is related to the pigmen