N-Nitrosodimethylamine-d6 is intended for use as an internal standard for the quantification of N-nitrosodimethylamine by GC- or LC-MS. N-Nitrosodimethylamine is a nitrosamine. It has been found in tobacco smoke, pesticides, alcoholic beverages, and several food products, including cured meats. Nitrosodimethylamine (50 mg/L in the drinking water) induces tumors in mice and inhalation at 0.2 mg/m3 induces tumors in rats.