Searching on the web I found that since the mid-1800, marshmallows are made of gelatin, cornstarch, corn syrup, and sugar, plus flavors and coloring. Before that, marshmallows were made from the roots of the mallow plant, a pink-flowered European perennial herb of the mallow family that is naturalized in the eastern U.S. As far back as ancient Egypt, people had squeezed the mallow root to make a sticky confection.

As nowadays the marshmallows are made of gelatin, I have to mention that gelatin is the processed version of a structural protein called collagen that is found in many animals, including humans. Collagen actually makes up almost a third of all the protein in the human body. It is a big, fibrous molecule that makes skin, bones, and tendons both strong and somewhat elastic.