Fused phenol derivatives of the formula (I): ##STR1## (wherein R.sup.1 and R.sup.2 each, independently, is H, halogen, trifluoromethyl, cyano, (substituted) alkyl, alkoxy, cycloalkyl, COOH, COOR.sup.6 (in which R.sup.6 is C1-6 alkyl), alkenyl or R.sup.1 and R.sup.2, taken together, is --CH.dbd.CH--CH.dbd.CH--, when R.sup.1 and R.sup.2 are ortho to each other; A is alkylene, alkenylene, oxyalkylene or ##STR2## (in which m is 1-6); B is a monocyclic hetero ring containing a nitrogen atom; G is --OR.sup.3A or --NR.sup.3B R.sup.3C (in which R.sup.3A, R.sup.3B and R.sup.3C each, independently, is H, alkyl, acyl, or alkoxyalkyl); R.sup.4 and R.sup.5 each, independently, is H, alkyl, or R.sup.4, R.sup.5 together with the carbon atom to which they are attached represent C4-7 cycloalkyl; and n is 1-3; non-toxic salts thereof, non-toxic acid addition salts thereof, and hydrates thereof. The compounds of the formula (I) have inhibitory activities on TXA.sub.2 synthetase and on 5-lipoxygenase and/or a scavenging activity on active oxygen species, and are useful for the prevention and/or the treatment of thrombosis, arteriosclerosis, ischemic heart diseases or brain diseases, bronchial asthma, renal inflammation, rheumatism, arthritis, gout, psoriasis, ulcerative colitis, trichophytosis, cardiac infarction, allergic diseases, etc.