... and drink this:
Medical researcher have developed a pretty reliable treatment for a formerly difficult to treat infection of the intestines, Clostridium difficile, which causes serious, and even life-threatening diarrhea. The treatment is to seed the colon with a culture of "healthy" intestinal flora. Where do you get "healthy" intestinal flora you might ask? Well, that's where it gets gross; from the feces of a person with healthy intestinal flora. And how is this administered? In the mouth, in the nose, or up the butt.
Once you get past the gross factor it makes a lot of sense. C. difficile infections are often caused by antibiotics which kill off the common, beneficial gut flora, and leave resistant bacteria like C. difficile.
Our bodies are co-adapted with a wide variety of bacteria, fungi and parasites, and there is growing evidence that exposure to a wide spectrum of things in childhood is actually beneficial to the development of the immune system. One example is childhood asthma, which is more common in children from cities who grow up largely without exposure to ordinary dirt and animals. This is of some amusement to me, as I had childhood asthma (I wouldn't wish it on anyone) and in accord with the dogma of the day, my mother attempted to make my environment as sterile as possible (it was probably too late to affect it by then, anyway). So let the kid kiss the dog and wallow in the dirt.