One of the most obvious areas of comparison, though one that is very difficult to compare due to the obviously disproportionate effects, was the spread of diseases. In short, Europeans were exposed to syphillis, while Native populations were devastated by plague, smallpox, measles, typhus, and a host of other diseases. The human transfer is also not comparable, as the exhange instituted an enormous influx of European and Africans into the New World.
Other, less devastating exchange items included domesticated animals. Here, as well, the exhange was disproportionate. Pigs, cattle, horses, chickens all accompanied European colonizers, with dramatic effects on New World diets. These animals also impacted the American landscape, as hogs, mostly allowed to run wild, destroyed native crops, which farmers had never previously needed to fence in. European markets, if not ecosystems, were flooded with various animal skins, especially deer and beaver.
Europeans also brought edible plants, including such now-ubiquitous items as onions, garlic, citrus fruits, peaches, and sugar. Native peoples quickly incorporated these foods into their diets, although sugar, along with rice, was primarily cultivated on large European-owned plantations rather than by native farmers. Europeans, on the other hand, returned with new varieties of beans, potatoes, and maize. These plants quickly became crucial staple crops in Europe, as did others, such as chili peppers and tomatoes, which flourished in the Mediterranean basin. It was in this exchange of plants that the exchange was perhaps the most comparable. European landscapes and diets were as altered by contact and colonization as were those of the New World.