DENVER -- A new reports warns about human breast milk that is sold online.
A study by Nationwide Children's Hospital in Columbus, Ohio shows that about 10 percent of breast milk purchased on the Internet had cows' milk in it as well.
The mixture can be harmful to babies with dairy allergies or other medical conditions.
Researchers say the findings suggest that some sellers intentionally add cows' milk or infant formula to the breast milk.
The study was published in the journal "Pediatrics."
To learn more about safely receiving and donating breast milk, visit the Mothers' Milk Bank.