Novel 3,4-dihydroxychalcone derivatives useful as a pharmaceutical material, and novel anti-inflammatory preparations. The 3,4-dihydroxychalcone derivatives are compounds of the formula [I], ##STR1## wherein X is a substituted phenyl group represented, e.g., by the formula (i), ##STR2## in which R.sup.1 is a hydrogen atom or an alkyl group and R.sup.2 is an alkyl group, an alkoxy group or an --OH group (excluding an OH-group in the 4-position)or salts thereof. The anti-inflammatory preparations contain one of the above 3,4-dihydroxychalcone derivatives as an active ingredient.