Five types of Tommee Tippee Sippee cups are being recalled because mould could grow inside the lid.
About 227,000 of them have been sold in Canada, another 3.1 million in the States.
They were sold between December 2014 and May 2016.
There may be an illness associated with this.
If you have one, stop using it and contact the manufacturer for a refund.
Here are the details at Health Canada.