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 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 , a sulfur atom, or an oxygen atom； R 11 represents a hydrogen atom, a C 1 - 6 alkyl group, or the like； B represents a C 6-14 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.
