For those who care, most marshmellows contain animal products and this CNBC story highlights a Loma Linda University researcher who is on the case. . .
Modern "marshmallows" are made with air-blown gelatin. Gelatin is probably the most repulsive of all animal products- made from rendering down the hooves, connective tissues, joints, eyeballs, brains and anything else that ends up in the sluice grates of the slaughterhouse floor. Originally, Marshmallows were made from the Marsh Mallows - a plant from Egypt. They were an expensive imported delicacy around the turn of the last century. Not too long after that, somebody found that you could make a fair approximation of the real Marshmallow texture by air-blowing gelatin and adding all sorts of other junk.
Props to Jeremy and Sharon Fujimoto-Johnson for sending over a link. Here's the first part of the story: