It makes perfect sense because the liver is the body's filter. It takes the blunt of all the abuse on our bodies, be it from stress, poor diet, infections, environmental toxins, metals, drugs etc.
If it's not functioning properly, everything else will get backed up, and nasty little bugs can get the upper hand. Just look at what happens to a swimming pool or a fish tank when the filter stops working. It will be green and moldy in a matter of days!