A method for the preparation of selected phosphopeptides having anticariogenic and other activities, comprising the steps of completely digesting a soluble monovalent cation salt of casein in solution with a proteolytic enzyme, adding a mineral acid to the solution to adjust the pH to about 4.7, removing any precipitate produced, adding CaCl2 to a level of about 1.0% w/v to cause aggregation of at least the selected phosphopeptides in said digested solution, separating the aggregated phosphopeptides from the solution through a filter having a molecular weight exclusion limit lying substantially within the range 10,000 to 20,000 while passing the bulk of the remaining phosphopeptides and solution, diafiltering the separated phosphopeptides with water through a filter and concentrating and drying the retentate.