Disclosed is a compound which has a low molecular weight and has an activity of enhancing the production of EPO and / or an activity of enhancing the production of
hemoglobin. Specifically disclosed is and EPO production
enhancer and / or
a hemoglobin production
enhancer comprising a 1-acyl-4-(substituted oxy, substituted amino, or substituted
thio)-1,2,3,4-tetrahydroquinoline derivative, more specifically a tetrahydroquinoline compound represented by general formula (1) [wherein R1, R2, R2′, R3 and R3′ independently represent a
hydrogen atom, a C1-6
alkyl group, or the like; R4, R5, R6, R7, R8, R9 and R10 independently represent a
hydrogen atom, a
halogen atom, a C1-6
alkyl group, or the like; A represents N—R11, a
sulfur atom, or an
oxygen atom; R11 represents a
hydrogen atom, a C1-6
alkyl group, or the like; B represents a C6-14
aryl group, or a 5- to 10-membered heterocyclic group; and n represents an integer of 0 or 1], a salt of the tetrahydroquinoline compound, or a solvate of the tetrahydroquinoline compound or the salt.