I just got back from a week long Spanish immersion class in Buenos Aires, Argentina. Although I encountered very little specifically laid out for those following a gluten free and/or dairy free diet, I did get by ok. Most restaurants / waitstaff understood my concerns, however, please keep in mind that I speak passable Spanish and only have severe reactions to dairy cross contamination (I wasn't sick at all). Also, like the U.S., quite a bit of their food is breaded and fried, and dairy features in their cuisine as well so you do have to be careful.
I did visit two 'dieteticas' (argentinian for 'health food store') and also found gluten free cookies easily in most supermarkets. Unfortunately, a lot of gluten free options there contained dairy, including all of the bread products! I had cookies in normal flavors: vanilla, chocolate, as well as an interesting thumb print cookie with something called Quince. I saw but did not purchase gluten free / dairy free Jamon (ham) flavored cookies and Pizza flavored cookies!
|Bread products "con Gluten" or "with Gluten" in English!|
The only eatery where I saw gluten free prominently displayed was at an ice cream shop in a mall. (They had two dairy free options lemon and strawberry.) Overall, I just stuck to simple meals - grilled meat/chicken/fish mostly.
If you are going to Buenos Aires, I would recommend checking out these articles and sites as well:
Gluten-Free Guidebook - Gluten Free Buenos Aires
Gluten-Free Guidebook - Buenos Aires Restaurants
Gluten Free Buenos Aires
You may also want to review these tips for traveling with dietary concerns: Traveling Dairy Free / Gluten Free
Updated - 5/24/11
Argh, Laura from Gluten Free Traveller did a much better job of finding all the best GF options in B.A. than I did. You can check out all of her Buenos Aires posts here: http://glutenfreetraveller.com/tag/buenos-aires/ or if you're going farther afield her South America posts: http://glutenfreetraveller.com/tag/south-america/ I only wish I had started following her blog sooner!