Perhaps you are a newbie at vegetarianism and have not heard of these yet. They are two common non-vegetarian items. Be sure to read the ingredient list of what you're eating to see if these are in your food.
GELATIN
http://en.wikipedia.org/wiki/Gelatin
It is found in Jell-O, some Pop Tarts (frosting), marshmallows, candy, etc.
"Gelatin (US spelling) or gelatine (British spelling) (used to make Jell-o and other desserts) is made from the boiled bones, skins and tendons of animals. An alternative substance is called Agar-Agar, which is derived from seaweed. Another is made from the root of the Kuzu. Agar-Agar is sold in noodle-like strands, in powdered form, or in long blocks, and is usually white-ish in color.
Some Kosher gelatins are made with agar-agar, most are not. Some things that are vegan that are replacing gelatin are: guar gum and carrageenan. Only some 'emulsifiers' are vegan. Gelatin is used in photography. Although the technology exists to replace photographic film, its price is currently prohibitive and there is insufficient demand. Hopefully, with the growth of vegetarianism and veganism, this situation will soon change."
http://www.ivu.org/faq/gelatine.html
RENNET/RENNIN
Most commonly found in cheese, rennet is "the lining membrane of the fourth stomach of the calf (and/or) a preparation or extract of the rennet membrane, used to curdle milk, as in making cheese…." Rennin, also found in cheese, is "a coagulating enzyme occurring in the gastric juice of the calf, forming the active principal of rennet and able to curdle milk."
http://www.wholefoodsmarket.com/products/specialty/rennet.htmlSO WHAT ARE YOUR OPTIONS?
"So what are your options if you want to continue eating cheese and remain vegetarian? There are quite a few possibilities. Microbial enzymes, or vegetable enzymes, which are neither vegetable, nor animal, but are microbes, are now used by several smaller cheese producers for many, if not all, of their cheeses. Most of these companies are smaller and make gourmet-style cheeses, although some larger companies do have vegetarian selections. At this time many of the larger cheese producing companies we contacted cannot guarantee that their cheeses are made without rennet. They often use a mixture of microbial enzymes and rennet."
