After 4 months of almost daily kava drinking I noticed that I haven't had the runs or loose stool or whatever one wants to call it, not once. Used to happen once or twice a month, I assumed due to a diet very high in fresh vegetables and fruits. Given that it's been 4 months now I'm inclined to think that it was not because of my diet at all but occasional stomach inflammation due to a chronic inflammatory condition I have, and which I think kava has suppressed.
I also haven't been sick in any way, even with winter and spring colds and flu all over the place here in Michigan, which leads me to think kava boosts one's immune system in general.