Figure 4. Plasma concentration–time profiles of total bilirubin in rats after intravenous administration of MTX at 500 mg/kg (A) and 1,000 mg/kg (B) alone and in co-administration with 100 mg/kg glycyrrhizin (GZ). Each point represents the mean±S.D. of four rats. Significantly different at *p<0.05 vs. MTX alone.