Specimens of breast milk were obtained from each breast in a lactating patient for a 24-hour period after a gadolinium-enhanced MR imaging examination was performed. A quantitative analysis of gadolinium content in specimens obtained at 2, 11, 17, and 24 hours after the intravenous administration of gadopentetate dimeglumine demonstrated that gadolinium is excreted in small amounts (total of 1.60 mumol during a 24-hour period) and in similar amounts from each breast. These results suggest that a waiting period of 24 hours, with active expression of breast milk from each breast, should provide a reasonable safety margin for allowing resumption of breast-feeding. Additional data will be required before establishing definitive recommendations.