Sarah Oudina, 21, left the home of some family members in Cartierville Sunday afternoon with her young son, Naim.
She was also found by police.
She does not have legal custody of the boy, who is in the care of another member of the family.
Const. Danny Richer said the mother is seriously ill and said police had reason to believe the child could have been in danger.
“The woman left home without money, without clothes and without food, so they don’t think she can be safe with the child,” Richer said.