Best Answer: marshmallows contain gelatin which is made by boiling bones, ligaments and tendons of animals. so they aren't vegetarian. there are lots of veg alternatives though.check on line stores or health food stores. Sweet Sara & some online vegan stores have some good vegan marshmallows.eah, its cheaper to use animal gelatin than it is to make marshmallows from the extract of the marshmallow plant. Its not a joke, there is a marshmallow plant it just doesn't grow marshmallows. Laura · 7 years ago. Thumbs up.