[Problems] To provide a pharmaceutical, in particular a compound which can be used as a therapeutic agent for irritable bowel syndrome (IBS). [Means for Solving Problems] It was found that a tetrahydroisoquinolin-1-one derivative having an amide group at the 4-position or a pharmaceutically acceptable salt thereof has an excellent bombesin 2 (BB2) receptor antagonistic action. It is also found that the tetrahydroisoquinolin-1-one derivative is highly effective on bowel movement disorders. From the above, the tetrahydroisoquinolin-1-one derivative of the present invention is useful as a therapeutic agent for diseases associated with a BB2 receptor, in particular IBS.Derivat tetrahidroizokvinolin-1-ona predstavljen formulom (I) ili njegova farmaceutski prihvatljiva so:u kojoj simboli u formuli imaju sledeća značenja:R1: (C1-6 alkilen koji može biti supstituisan grupom odabranom iz grupe koju čine fenil koji može biti supstituisan halogenom, C1-6 alkilom ili -OR0, i -OH)-OH ilicikloalkil supstituisan grupom odabranom između grupe koju čine -OR0, -N(R0)2, -N(R0)C(O)R0, -N(R0)C(O)- C1-6 alkilen-OR0, -N(R0)S(O)2-C1-6 alkil, i heterociklična grupa,R0: isto ili različiti jedan od drugog, gde svaki predstavlja -H ili C1-6 alkil,R2: fenil koji može biti supstituisan halogenom il i-OR0,R3: -H,R4: -N(R0)- O-C1-6 alkilen-(aril ili heteroaril, koji može biti svaki supstituisan grupom odabranom iz grupe G6),Grupa G6: halogen, C1-6 alkil koji može biti supstituisan sa -OR0, halogen-C1-6alkilom koji može biti supstituisan sa -OR0, -CN, -N(R0)2, -CO2R0, -CO2-C1-6-alkilen-arilom, -C(O)N(R0)2, C1-6alkilen-OC(O)R0, C1-6alkilen-OC(O)arilom, C1-6alkilen-CO2R0, halogen-C1-6alkilen-CO2R0, C1-6 alkilen-CO2-C1-6 -alkilen-arilom, C1-6 6alkilen-C(O)N(R0)2, halogen-C1-6 alkilen-C(O)N(R0)2, -O-C1-6alkilen-CO2R0, -O-C1-6 alkilen-CO2-C1-6 -alkilen-arilom, -O-C1-6alkilen-C(O)N(R0)2, -O-halogen-C1-6 alkilen-CO2R0, -O-halogen-C1-6 alkilen-C(O)N(R0)2, -C(O)N(R0)S(O)2-C1-6alkilom, C1-6alkilen-C(O)N(R0)
