Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (EVG/COBI/FTC/TAF) is specified in its package insert to be taken with food to obtain sufficient exposure of EVG. It has been reported that a nutritional protein-rich drink shows comparable pharmacokinetics (PK) of EVG to those with a standard breakfast. In this study, the PK profiles of EVG and COBI were evaluated by administration of a single dose of EVG/COBI/FTC/TAF, after ingestion of either a nutritional protein-rich drink, milk, or apple juice. The geometric means for C and AUC of EVG following milk ingestion slightly decreased by 21% and 14%, respectively, and those following apple juice ingestion decreased by 67% and 61%, respectively, compared with a nutritional protein-rich drink. There were no differences in any PK parameters of COBI. Therefore, taking EVG/COBI/FTC/TAF after milk or apple juice ingestion appeared to be not appropriate. However, for plasma trough concentrations (C ), it is known that C is best correlated with the efficacy of EVG. The mean C of EVG after milk ingestion was 620.6 ng/mL, which was more than 10-fold the protein binding-adjusted 95% inhibitory concentration. With all the above considerations, it was concluded that taking EVG/COBI/FTC/TAF with milk could be an option to maintain sufficient plasma concentrations of EVG.