PURPOSE: To describe the mammographic features of metallic punctate densities seen in women who were treated with the herb go-yak for breast abscess and to explain the cause of these findings. MATERIALS AND METHODS: Mammograms showing metallic punctate densities that appeared to be microcalcifications in 34 women were analyzed retrospectively with attention to the location, shape, distribution, and depth of the lesions. In all patients, go-yak was applied into the open wound after abscess drainage 6-42 years before mammography. In six patients, histopathologic specimens were obtained after needle localization. RESULTS: Metallic densities were in the subareolar or central breast in 24 (71%) of 34 patients. The shape was predominantly round or punctate in all patients, but rod-shaped or linear lesions were found in seven patients. The distribution and depth of lesions were variable, but they extended to the subcutaneous fat in 29 patients (85%). A high concentration of lead was found in the histopathologic specimens and herb samples. CONCLUSION: Lead deposits associated with go-yak treatment should be included in the differential diagnosis when the suspected microcalcifications are of unusually high density, are central in location, and extend into the subcutaneous fat in Asian women with a history of breast abscess.