The 1999 *JCI* article by Eichelbaum et al. reported that the absorption of orally administered digoxin is influenced by the expression of intestinal P-glycoprotein (P-gp). Rifampin treatment significantly reduced digoxin plasma concentrations, both orally and intravenously, and increased intestinal P-gp content by 3.5 ± 2.1-fold. This increase in P-gp correlated with the area under the plasma concentration curve (AUC0–144h) after oral digoxin administration. The authors concluded that intestinal P-gp affects digoxin bioavailability, and the decrease in oral bioavailability during rifampin treatment is due to P-gp induction. Win L. Chiou, Sang M. Chung, and Ta C. Wu from the University of Illinois at Chicago raised two issues: misassignment of data pairs in the original study and the calculation of oral digoxin bioavailability. The authors corrected the data and confirmed the significant relationship between AUC0–144h and P-gp levels, with minor changes in Spearman rank correlation and significance levels. They also explained the calculation of oral digoxin bioavailability, using AUC0–144h and AUC0– from the control period. Despite some differences in recalculated values, the principal findings and conclusions of the study remain valid.The 1999 *JCI* article by Eichelbaum et al. reported that the absorption of orally administered digoxin is influenced by the expression of intestinal P-glycoprotein (P-gp). Rifampin treatment significantly reduced digoxin plasma concentrations, both orally and intravenously, and increased intestinal P-gp content by 3.5 ± 2.1-fold. This increase in P-gp correlated with the area under the plasma concentration curve (AUC0–144h) after oral digoxin administration. The authors concluded that intestinal P-gp affects digoxin bioavailability, and the decrease in oral bioavailability during rifampin treatment is due to P-gp induction. Win L. Chiou, Sang M. Chung, and Ta C. Wu from the University of Illinois at Chicago raised two issues: misassignment of data pairs in the original study and the calculation of oral digoxin bioavailability. The authors corrected the data and confirmed the significant relationship between AUC0–144h and P-gp levels, with minor changes in Spearman rank correlation and significance levels. They also explained the calculation of oral digoxin bioavailability, using AUC0–144h and AUC0– from the control period. Despite some differences in recalculated values, the principal findings and conclusions of the study remain valid.