Abstract: A hydroxystyrene derivative represented by the formula (I): ##STR1## Wherein when R.sup.1 and R.sup.2 : phenyl group, benzyl group or phenethyl group, or R.sup.1 : R.sup.5 O--(R.sup.5 : H, a C.sub.1 to C.sub.5 alkyl group or benzyl group) and R.sup.2 : benzyl group or PhSCH.sub.2, R.sup.3 and R.sup.4 are taken together to represent --CONH--CS--S--, ##STR2## (X.sub.1 : H, a halogen, methyl group, ethyl group, R.sup.7 O--(R.sup.7 : methyl or ethyl group), nitro group, aminosulfonyl group or amino group, m.sup.1 : 1 or 2), pyridyl group, furyl group or thienyl group, n.sup.1 : an integer of 0 to 3); when R.sup.1 and R.sup.2 : phenyl group, benzyl group or phenethyl group, or R.sup.1 : R.sup.5 O--(R.sup.5 : as defined above) and R.sup.2 : benzyl group, R.sup.3 : cyano group and R.sup.4 : a carbamoyl group, or R.sup.3 and R.sup.4 are taken together to represent --CO--Y--CH.sub.2 CH.sub.2 --(Y: O or --NH--) or ##STR3## and when R.sup.1 and R.sup.2 : a C.sub.1 to C.sub.3 alkyl group, R.sup.3 and R.sup.