SOD1 and Erythema: As 200 – 300 Joule/m2 effective is used as the value of 1 MED for comparative safety purpose for white skin, the fact that in Bufo arenarum embryos SOD activity at 2 hr post exposure increases about 8 times in a wide range of doses from 200 to 800 J/m2 could open the possibility to employ SOD activity, at least in this amphibian embryo, as an alternative test for erythema studies.