NEW MATERIAL:A tetrahydronaphthalene derivative shown by the formula I (R1 is H, or lower alkyl; n is 1W5; with the proviso that the case where substituent group shown by the formula II is bonded to the 6-position of 1,2,3,4-tetrahydronaphthalene skeleton is omitted) and its salt.

EXAMPLE: 7-( 1-Imidazolylmethyl )-5,6,7,8-tetrahydro-2-naphthalenecarboxylate hydrochloride.

USE: Having an inhibitory action on thromboxane A2 synthesis, useful as a preventive and remedy for ischemic cardiac diseases such as angina pectoris, myocardial infraction, cerebrovascular disease, and thrombosis.

PREPARATION: For example, a compound shown by the formula II (R2 is lower alkyl; X is arylsulfonyloxy, alkylsulfonyloxy, etc.; n is 2W5) is reacted with imidazole and sodium hydride or potassium tertiary butoxide in dimethylformamide, to give a compound shown by the formula I.