Abstract: Carbostyril derivatives useful for inhibiting the adhesion of platelets represented by general formula ##STR1## [wherein, R.sup.1 is a hydrogen atom, a fluorine atom or a methyl group; R is a group of the formula ##STR2## (R.sup.2 is a methyl group, a trifluoromethyl group or a nitro group), or a group of the formula ##STR3## (R.sup.3 is a fluorine atom and p is an integer of 2 or 3); and n is an integer of 2 or 3], or salts thereof.Said carbostyril derivatives or salts are useful as an agent for inhibiting the adhesion of platelets.

Abstract: The novel carbostyril derivative represented by the general formula (1) ##STR1## [in the formula, A, R.sup.1, R.sup.2 and the carbon-carbon bond between 3- and 4-positions in the carbostyril skeleton have the same definitions as above] has an excellent platelet aggregation inhibitory activity, a phosphodiesterase inhibitory activity, a venticular contraction activity (a positive contraction activity), an anti-ulcer activity, an anti-inflammatory activity, a cerebral blood flow increasing activity, a thrombus dissociation activity, a thromboxane A.sub.2 antagonism activity, etc. The carbostyril derivative of the present invention is characterized in that it exhibits the above activities for a long time, is low in toxicity (particularly low in toxicity to hearts of cardiovascular hyperplasia, myocardipathy, etc.), and is low in circulation activities such as heart rate increasing activity, blood pressure decreasing activity and the like.

Abstract: Carbostyril compounds or salts thereof of the formula ##STR1## wherein A is a C.sub.1 -C.sub.6 alkylene group; R.sup.1 is a C.sub.3 -C.sub.8 cycloalkyl-C.sub.1 -C.sub.6 alkyl group which may have, as a substituent, a group selected from the group consisting of C.sub.1 -C.sub.6 alkoxycarbonyl groups, a carboxy group, C.sub.2 -C.sub.6 alkanoyloxy-C.sub.1 -C.sub.6 alkyl groups, amino-C.sub.1 -C.sub.6 alkyl groups, C.sub.1 -C.sub.6 alkylamino-C.sub.1 -C.sub.6 alkyl groups and hydroxy-C.sub.1 -C.sub.6 alkyl groups, a C.sub.3 -C.sub.8 cycloalkyl group, a tetrahydropyranyl-C.sub.1 -C.sub.6 alkyl group, a C.sub.1 -C.sub.3 alkylenedioxy group-substituted C.sub.1 -C.sub.6 alkyl group, a phenyl-C.sub.1 -C.sub.6 alkyl group having, as a substituent on the phenyl ring, 1 to 3 groups selected from the group consisting of C.sub.1 -C.sub.6 alkyl groups and a hydroxyl group, or a piperidinyl-C.sub.1 -C.sub.6 alkyl group having a C.sub.1 -C.sub.6 alkyl group as a substituent; R.sup.