The objective of the present study is to contribute to establishing in vivo phenotyping procedures for organic anionic transporter polypeptide 1B1 (OATP1B1), organic cation transporters 1 and 2 (OCT1/2), multidrug and toxic compound extrusion transporters 1 and 2,kidney splice variant (MATE1/2K), organic anion transporters 1 and 3 (OAT1/3), and p-glycoprotein (P-gp) transporters via a cocktail approach. To this end, marker substrates for each of the respective transporters are administered as single doses in one period each and as a cocktail in one period to 24 healthy volunteers, and phenotyping metrics are derived from plasma and urine concentrations.