Why do some people stay fit and healthy easier than others, even when following the same health advice? Why does the same medication work well in one person, but not in another? Some of our individuality in these regards may trace to which bacteria we carry in the soil of our intestinal gardens. In this talk, drawing on work by my own research lab at the Charité and on that by our collaborators and rivals elsewhere in the world, I outline what we know, what we speculate, and what obstacles remain in the way of widespread adoption of personalized health prevention through microbiome sequencing.