Disclosed is a low-molecular-weight compound having an EPO production-promoting activity and/or a hemoglobin expression-enhancing activity. Specifically disclosed is an EPO production promoter and/or a hemoglobin expression enhancer comprising a 1-acyl-4-(phenoxy, benzyloxy or phenylamino)-1,2,3,4-tetrahydroquinoline derivative, more specifically a tetrahydroquinoline compound represented by the general formula (1)； [wherein R 1 , R 2 , R 2' , R 3 and R 3' independently represent a hydrogen atom, a C 1-6 alkyl group, or the like； R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 independently represent a hydrogen atom, a halogen atom, a C 1-6 alkyl group, or the like； A represents N-R 11 or an oxygen atom； R 11 represents a hydrogen atom, a C 1-6 alkyl group, or the like； 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.
