Is it bad to drink your own breast milk?

No: Breast milk is very nutritious, and excellent for babies, so will be of no harm to adults (in small amounts). Breast milk is too rich, so will give an adult too much animal fat (yes, we are animals) and many extra calories. Most moms with excess breast milk just freeze it for use later when their babies are weaned off the breast, but surely some frozen milk gets wasted (thrown away).