Use of marijuana and cannabinoids has been on the rise in current years, like in childbearing girls. This has resulted in cannabinoids getting additional often identified in breast milk as a outcome of its higher lipid content material and cannabinoids possessing a higher lipophilicity, thereby exposing the breastfeeding infant to cannabinoids and other marijuana constituents. Presented is a approach for the evaluation of Δ9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol ( CBD) in breast milk. THC, CBN, CBD and their isotopically labeled requirements have been extracted from breast milk making use of a modified QuEChERS approach and analyzed making use of ultra-overall performance liquid chromatography and tandem mass spectrometry. As a outcome of the higher lipid content material of breast milk, saponification of the lipids was needed to boost general extraction efficiency. The method efficiency percentage for THC, CBD and CBN are 55%, 80% and 25%, respectively. The recovery percentage for THC, CBD and CBN are 95%, 118% and 85%, respectively. The matrix impact percentage for THC, CBD and CBN are 53%, 66% and 26%, respectively. Linearity was assessed from 1 to 100 ng/mL for THC, CBN and CBD and had r2 > 0.996. Validation controls have been ready at 1, three, 20, 80 and 300 ng/mL (dilution handle), and the bias was determined to be much less than ±20% with %CVs <15% for all controls. Due to the restricted access of genuine breast milk for routinely preparing matrix matched calibration and handle components, Enfamil® Premium™ Newborn Infant Formula (-3 months) was evaluated as a breast milk substitute. No considerable variations have been observed for THC, CBN and CBD making use of either breast milk or formula as the matrix therefore, it was determined to be an acceptable breast milk matrix substitute. The modified QuEChERS approach was determined to be a robust, reputable approach for the determination of THC, CBN and CBD in breast milk.