A social media group set up to connect breast milk donors with mothers in need has posted a warning after learning one woman was allegedly selling donated milk for profit.

Human Milk 4 Human Babies said it received a flood of messages over the weekend about a member who had apparently been taking advantage of others' generosity.

"We are of course extremely disappointed that something loving and altruistic has been abused by someone looking to cash in, but we know our community is full of wonderful people who just want to make sure babies are fed human milk," the group told CTV News in a statement.

After investigating, Human Milk 4 Human Babies banned the woman at the centre of the allegations from its Facebook group, and posted a warning to its thousands of members to beware.

The group told CTV News it has never come across an issue like this before.

"Our values are informed choice and transparency and altruism," it said. "She has no place here and we are very disappointed."

Members were outraged, with some recounting multiple meetings to donate their breast milk to the woman.

Vancouver resident Myriam Steinberg was among them. She told CTV News she donated to her on two occasions, but stopped after feeling something was off about her.

After she heard the milk was being sold, she was so upset she couldn't sleep.

"It feels gross. It feels like a betrayal," Steinberg said. "Any woman who pumps knows it's a lot of work … so when you get to the point where you're ready to give it away, you want to know that it's going to a baby that you know is going to benefit from it."

Group members who donate strive to be open about what they've been eating and drinking, so recipients can make an informed decision about what they're giving their babies. Steinberg said she hopes the women who purchased the donated milk were provided the same kind of information.

"You just want the best for the baby," she said.

According to Human Milk 4 Human Babies, the woman went by different names online. CTV News has not confirmed her identity.

It's also legal to privately sell human donor milk – though Health Canada recommends against it for safety reasons.

"Obtaining human milk from the Internet or directly from individuals raises health concerns because, in most cases, medical information about the milk donors is not known. The Canadian Paediatric Society does not endorse the sharing of unprocessed human milk," the agency said in a 2010 alert.

"Health Canada recommends that Canadians consult their health care professional should they have questions about breastfeeding or if they are considering purchasing human milk or acquiring it through the Internet or directly from individuals."

Human Milk 4 Human Babies also advises members against ever paying for milk, because "you never know whose milk it is or if it is even breast milk."

The B.C. RCMP has yet to respond to a request for comment.