Vitamins C and E were selected for analysis in this patient to study the effect of megavitamin ingestion on water-soluble and milk-fat-soluble vitamin concentration. This mother also had chronically consumed megadose amounts of vitamins A, B-6, B-12, and thiamin. Although these vitamins were not quantitated in her milk, one would anticipate that they were elevated, as were vitamins C and E. Long-term megavitamin intake of vitamins C and E, 40 and 99 times the RDAs, respectively, was associated with elevated blood and milk vitamin levels. The thesis that dietary water-soluble but not fat-soluble vitamins alter milk vitamin concentrations was not supported. Milk vitamin C levels were elevated above established norms, and milk vitamin E levels were more than three times the upper range of normal.