Police in Hamilton, Ont., are warning parents to sift through their children's Halloween candy after one child received Zyban pills.

Zyban is an oral prescription medication used as an aid to stop smoking.

Hamilton police were called Wednesday night after some Zyban pills were found in a child's candy bag. The pills are purple and resemble the shape and size of Smarties or Skittles candies.

If a child ingests the drug, it could cause health complications.