Cationic tetrahydropyrazopyridine of formula (1), optical and geometric isomers thereof, addition salts thereof and / or solvates thereof: ** Formula ^ ** in whose formula (1): * Rl, R3, R4 Y R5 independently represent each other a hydrogen atom； a halogen atom； a linear or branched C1-C4 alkyl radical； a linear or branched Cl-C4 hydroxyalkyl radical； * R2 Y R3, R3 Y R4 or R4 Y R5 can form, together with the carbon atoms to which they are attached, a ring of 5 to 8 saturated, unsaturated or aromatic atoms optionally substituted with one or more radicals selected from hydroxyl radicals , alkoxy, Cl-C4 alkyl and hydroxyalkyl Cl-C4； * Zl represents an oxygen atom or an NRs group； * Rs represents a hydrogen atom or a linear or branched C1-C4 alkyl radical； * R1 represents: - a linear or branched C1-C20 alkyl radical, substituted and / or interrupted by a cationic radical, said alkyl radical being optionally interrupted by one or more oxygen atoms and / or by one or more NR6 groups, optionally substituted with one or more radicals selected from hydroxyl and Cl-C4 alkoxy radicals or hydroxyalkyl radicals； - a saturated or unsaturated or aromatic heterocycle or ring of 5 to 8 atoms substituted with a cationic radical and optionally substituted with one or more radicals selected from hydroxyl radicals and Cl-C4 alkoxy or hydroxyalkyl radicals； * when Zl represents a group NRs then: R1 and Rs can form, together with the nitrogen atom to which they are attached, a mono or polycationic heterocyclic, preferably monocationic, of 5 to 8 atoms saturated, unsaturated, aromatic or non-aromatic, optionally substituted with one or more radicals selected from Cl-C4 alkyl, hydroxyl, Cl-C4 alkoxyamino, (Cl-C4) alkylamino, dialkylamino (Cl-C4), thio-SH, alkylthio (Cl-C4), carboxyl, C (O ) OH or C (O) O-, M + representing M +, which may be present or absent depending on the cationic charge number of the compound (1), an alkali metal, alkaline earth metal or ammonium； alkylcarbonyl (Cl-C4)；
