Let's say there are a couple of herbs that people believe help prevent the flu. So to test this, what we do is we wait for flu season, and we randomly assign people to three different groups. And over the course of flu season, we have them either in one group taking herb 1, in the second group taking herb 2, and in the third group they take a placebo. And if you don't know what a placebo is, it's something that to the patient or to the person participating, it feels like they're taking something that you've told them might help them, but it does nothing. It could be just a sugar pill, just so it feels like medicine. The reason why you even go through the effort of giving them something is because oftentimes there's something called a placebo effect, where people get better just because they're being told that they're being given something that will make them better. So this could right here just be a sugar pill.