The pharmacokinetics of lithium carbonate were investigated in rabbits with folate-induced renal failure. The blood level, the area under the blood concentration curve (AUC) and the biological half·life were increased significantly, and the urinary excretion was decreased significantly compared with those of normal rabbits. Correlation of serum creatinine concentration and AUC, biological half-life, and correlation of creatinine clearance and renal clearance of lithium carbonate have linear relationship respectively. In short, dosage regimen of lithium carbonate is considered to be adjusted in the dose size and the dosing interval by degree of experimental renal failure.