Tricyclic compounds represented by formula (I):
wherein

represents single bond or double bond; X 1 -X 2 represents -CH 2 O-,
wherein t represents 0, 1 or 2, -CH 2 -CH 2 -, or -CH=CH-; W represents -S-or = CH-; n is 1, 2, 3, or 4; one of R A and R B represents hydrogen and the other represents -Y-M wherein Y represents single bond, -CR 1 R 2 -(CH 2 ) m -, or -CR 1 =CR 2 -(CH 2 ) m wherein each of R 1 and R 2 independently represents hydrogen or lower alkyl and m is 0, 1, 2, 3 or 4, in which the left side of each formula is bound to the mother nucleus; and M represents -COOR 3 wherein R 3 represents hydrogen or lower alkyl, -CONR 3a R 3b wherein each of R 3a and R 3b independently has the same significances for R 3 as described above, or tetrazolyl; each of G A and G B independently represents lower alkyl, halogen, hydroxyl, or lower alkoxyl; each of g A and g B independently represents 0, 1, 2 or 3; Z represents N-E 1 -Q wherein E 1 represents single bond, -CO-, -COO- wherein the left side of the formula is bound to the nitrogen atom, or -S0 2 -; and Q represents optionally substituted aryl, optionally substituted aralkyl, optionally substituted aralkenyl, aromatic heterocyclic group, or

wherein L represents hydrogen, hydroxyl, or lower alkoxy; E 2 represents single bond, -CO-, or - wherein R 4 represents hydrogen or lower alkyl; and Q has the same significance as described above; C = CH-Q wherein Q has the same significance as described above; or
p is 1, 2 or 3; possess a potent antagonizing action against thromboxane A 2 and also an antiallergic and/or antihistaminic activity, and are expected to have preventive and therapeutic effects on ischemic diseases, cerebro-vascular diseases, etc.