Passive cutaneous anaphylaxis (PCA) was elicited both in the ear and in the dorsal skin of 13 strains of mice at the same time and assessed quantitatively by measuring the amount of extravasated dye. Body pigments of colored mice such as DBA/2 (chocolate), C3H/He (brown) and C57BL/6 (black) did not interfere with the measurement of dye. In the ear response, ICR was a higher responder, C57BL/6 and BALB/c-nu/nu were lower responder strains. In the dorsal skin response, however, ICR was a lower responder, BALB/c-nu/nu, Hairless and WBB6 F1- +/+ were higher responders. WBB6 F1-W/WV was a nonresponder in both responses. The ear response was highly reproducible and the dorsal skin response of each strain was 1/2–1/10 of its ear response except for BALB/c-nu/nu. The PCA bluing regions on the dorsal skin of BALB/c-nu/nu were clearly delineated and the response was almost comparable to its ear response.