Abstract: Carbostyril derivatives and salts thereof represented by the general formula (1a), including some known compounds, possess activities for inhibiting adhesion of thrombocytes. ##STR1## Z, A, X, R, R.sup.1 and R.sup.2 are defined in the specification. Some carbostyril derivatives having chemical structural formulas similar to those of carbostyril derivatives and salts thereof represented by the general formula (1a) have been known in prior art references, however the above-mentioned pharmacological activities have not been known to the present date.

Abstract: A carbostyril derivative or pharmaceutically acceptable salt thereof represented by the following general formula: ##STR1## wherein Z, A, XN, R, R.sup.1, and R.sup.2 are as defined in the specification. These carbostyril derivatives are useful in pharmaceutical compositions for inhibiting adhesion of thrombocytes.

Abstract: Benzo-heterocyclic compounds of the formula: ##STR1## wherein R.sup.1 is a lower alkyl group; R.sup.2 is a halogen atom or a group of the formula ##STR2## (wherein R.sup.4 and R.sup.5 combine together with the nitrogen atom to which they bind to form a 5- or 6-membered saturated heterocyclic group which may optionally contain an oxygen atom or nitrogen atom within the ring as an additional hetero atom and may also optionally have a substituent selected from a lower alkyl or hydroxy group on the hetero ring); R.sup.3 is an amino or nitro group; X is a halogen atom; and n is an integer of 1 or 2, and a salt thereof, which have excellent antimicrobial activities and are useful as an antimicrobial agent, or as an intermediate for the preparation of an active compound.