The present invention relates to prevention or treatment a brain edema, an intracranial hemorrhage and a cerebral infarction by administering a pharmaceutically effective amount of a compound or a pharmaceutically acceptable salt thereof, for inhibiting a vascular permeability enhancer, which the compound is of the formula: ##STR1## wherein A is halogen, --X--R.sup.3 in which X is O, S, NH or NHNH, and R.sup.3 is H, acyl, a hydrocarbon group or an aromatic heterocyclic group, or --Y.dbd.R.sup.4 in which Y is N or NHN, and R.sup.4 is a divalent hydrocarbon group, and R.sup.1 is H, halogen, a hydrocarbon group, a heterocyclic group or --Z--R.sup.5 in which Z is O, S or NH, and R.sup.5 is H, a hydrocarbon group or an aromatic heterocyclic group;R.sup.2 is H, halogen, a hydrocarbon group or a heterocyclic group;B is --W--R.sup.6 in which W is CH.sub.2, CO or CS, and R.sup.6 is OH, alkoxy, acyloxy, alkylsulfinyl, alkylsulfonyl, phosphoric acid or amino, or B together with E form a cyclic phosphoric ester; andD and E are H, amino, azido, halogen or OH.