My guess is its the sweet stuff that attrcts them like antifreeze does.
I believe the active ingredient to cause this in anti freeze as well as other solvents etc is ethylene glycol or methanol.
http://health.allrefer.com/health/et...ycol-info.html
it only takes half a cup of antifreeze to kill someone, and have seen women use it to kill husbands, put it in gatorade and no one will know.
scary stuff, its odorless and its sweet to the taste.