Being a vegetarian in Argentina is difficult, youll get some surprised stares and a lot of eggplant for dinner (grilled, roasted, a la pizza, you name it, but its always eggplant). When eating out i mostly lived on pizza, or a simple pasta dish if the sauce didnt have meat. Its doable but youll have to cook a lot yourself (which isnt necessarily a problem if you like cooking, veggies are everywhere and cheap). When i went to Chile i found it to be a bit easier, and people more understanding. I went to have lunch with friends at some cheap, not very interesting place, and the waitress without me asking it informed me the dessert contained gelatine. After the laughs and blank stares of Buenos Aires, i was pleasently surprised by that. I think in all of South America meat is a pretty big part of food, so just count on that. Ive never been in the north of South America but i hear the fruit is fantastic, which for me as a veggie would be great. Argentina has very very good icecream though, and i loooove pizza.