A simple disposable chemical UVB radiation dosimeter with silver-mercu
ry-oxalate suspension, SUNTEST, was developed for use by the general p
ublic. Its spectral sensitivity curve closely matches the erythemal ac
tion spectrum. SUNTEST takes account of the variables influencing the
length of sunbathing. The dose of solar UV radiation can be evaluated
from the darkening of the dosimeter, from white to dark brown. On the
basis of the results of a 5 min exposure, recommendations are given fo
r safe exposure times (which do not produce sunburn) for different ski
n types. Regular use of this simple UVB dosimeter will contribute to t
he prevention of acute adverse effects of solar exposure; like any lim
itation of UV exposures, it may be expected to reduce also the late ad
verse effects, including skin malignancies.