Substance for use in the treatment of uremia in patients suffering from chronic renal failure, in which said substance comprises, as an effective ingredient, a compound of general formula (I): ** Formula ** [in which R1 is (A) COOR2, wherein R2 is 1) hydrogen or a pharmaceutically acceptable cation, 2) C1-C12 linear alkyl or C3-C14, 3) -Z-R3 branched alkyl, wherein Z is a covalent bond, or linear alkylene or branched represented by CtH2t in which t is an integer from 1 to 6, R3 is C3-C12 cycloalkyl or C3-C12 cycloalkyl substituted with 1 to 3 R4 in which R4 is hydrogen or C1-C5 alkyl, 4) - (CH2CH2O ) nCH3, in which n is an integer from 1 to 5, 5) -Z-Ar1, in which Z represents the same meanings as described above, Ar1 is phenyl, a-naphthyl, b-naphthyl, 2 -pyridyl, 3-pyridyl, 4-pyridyl, a-furyl, b-furyl, a-thienyl, b-thienyl or substituted phenyl (in which the substituent or substituents are at least one d and chlorine, bromine, fluorine, iodine, trifluoromethyl, C1-C4 alkyl, nitro, cyano, methoxy, phenyl, phenoxy, p-acetamidabenzamide, -CH>； = N-NH-C (>； = O) -NH2, -NH- C (>； = O) -Ph, -NH-C (>； = O) -CH3 and-NH-C (>； = O) -NH2), 6) -CtH2tCOOR4, in which CtH2t and R4 represent the same meanings as described above, 7) -CtH2tN (R4) 2, in which CtH2t and R4 represent the same meanings as described above, 8) -CH (R5) -C - (>； = O) -R6, in that R5 is hydrogen or benzoyl, and R6 is phenyl, p-bromophenyl, p-chlorophenyl, p-biphenyl, pnitrophenyl, p-benzamidaphenyl or 2-naphthyl, 9) -CpH2p-W-R7, where W is -CH >； = CH-, -CH>； = CR7- or -C≡C-, in which R7 is hydrogen, linearly branched C1-C30 alkyl or C7-C30 aralkyl, p is an integer from 1 to 5, or 10) -CH (CH2OR8) 2, where R8 is C1-C30 alkyl or acyl, (B) -CH2OH, (C) -C (>； = O) N (R9) 2, where R9 is hydrogen, linear alkyl C1-C12, branched C3-C12 alkyl, C3-C12 cycloalkyl, C4-C13 cycloalkylalkylene, phenyl, substituted phenyl (in the that the definition or definitions of the substituent or substituents are th
