A review of the literature and the experiments reported in this paper demonstrate that two most important factors must be considered in any estimation of a "normal" skin histamine level, namely, (1) the region from which the skin was taken, and (2) the method of tissue extraction used. 1. Region from Which Skin Was Taken Feldberg and Miles1 demonstrated a striking regional variation in skin histamine levels in the guinea pig, and this finding has been confirmed.2 It was, therefore, considered most likely that a similar variation might occur in humans, though a review of the literature failed to reveal any significant information on this point. The present study is of skin histamine levels in 13 cases of traumatic sudden death: 12 by automobile accidents, and 1 a traumatic air embolism. All derminations were run within 24 hours of death (from prior guinea pig experiments,