When Sarah Douglas took a sip from what she thought was a latte at a McDonald’s in Lethbridge, Alta., she got a mouthful of cleaning solution instead.

There was an immediate “burning” feeling, she told CTV Calgary. “My tongue felt fuzzy and my mouth felt almost numb.”

When she went back to the restaurant to talk to staff, they discovered that the machine pumping out lattes was still attached to cleaning solution instead of coffee.

The franchise owner has apologized to Douglas, whose symptoms were monitored by poison control. She has not suffered any health effects, but was told if she develops shortness of breath or difficulty swallowing she should go to the hospital.

Alberta Health Services is investigating the incident.

With a report from CTV Calgary