A hydroquinone derivative useful as an intraocular pressure lowering, anti-hypertensive and radical scavenging agent represented by the following formula
1
wherein B
1
and B
2
in formula (I) are the same or different and at any position on the benzene ring (when W is nitrogen, however, at any other position on the benzene ring) and each denotes a substituent selected from the group consisting of hydrogen, halogen, hydroxyl, lower alkoxyl and carboxyl, and the substituent CH
3
is at position
2
or
3,
and W are the same or different and each denotes a nitrogen or carbon atom. R
1
, R
2
, R
3
and R
4
in formula (II) are the same or different and each denotes a substituent selected from the group consisting of hydrogen, lower alkyl and lower alkoxyl, and B
1
and B
2
are as hereinbefore defined, or a pharmacologically acceptable salt thereof.
A hydroquinone compound is represented by the following formula
or a pharmacologically acceptable salt thereof with W, R, R1-4, and B1-2 defined herein.