The phrase "bad germs" refers to harmful microorganisms that can make us sick. These germs can cause diseases and infections in our bodies. Full definition
It can fight bad germs in the body or perform functions, such as producing vitamins, that support human health. (sciencenewsforstudents.org)
But what we've learned over the past couple of decades is that there are not only bad germs, but there are also good germs, and those are probiotics. (biohmhealth.com)
It's not good enough to just take a probiotic, because good germs can not balance out bad germs if you can't reach them. (mindbodygreen.com)