A flavoring system for a liquid pharmaceutical composition and pharmaceutical compositions containing such flavoring systems are disclosed. Flavoring systems of the invention include at least one sweetening agent, at least two flavored ingredients, and at least one flavor modifier selected from the group consisting of citric acid, sodium citrate, sodium chloride, and mixtures thereof. At least two of the flavored ingredients are selected from the group consisting of a vanilla flavored ingredient, a peppermint flavored ingredient, a menthol flavored ingredient, a cotton candy flavored ingredient, and mixtures thereof. The one or more sweetening agents comprise glycerin, monoammonium glycyrrhizinate, saccharin sodium, acesulfame potassium, high fructose corn syrup, and/or mixtures thereof. Pharmaceutical compositions of the invention include a flavoring system of the invention, a solvent system, and at least one pharmaceutically active agent, such as lopinavir or derivatives thereof, ritonavir or derivatives thereof, or mixtures thereof. Methods for making such liquid pharmaceutical compositions are also disclosed.