Police arrested Christine Allen, 32, of Kitchener. Investigators said she may have also used the name Christine Keilbar.
"The lady that's charged used to operate a daycare in Kitchener from 2009 to 2011 and there are concerns that other kids may have been victimized," Waterloo Police Inspector Kevin Thaler said Monday.
"The allegation is that an over-the-counter eye care product was administered to the two children. When ingested, this is very dangerous," he said.
Allen faces two counts of aggravated assault and one count of administering a noxious substance.
More to come