Some are good, some are bad, and some can make you sick. We can get ear infections, sinus infections, sore throats, pneumonia.
Bacteria can cause diarrhea.
Salmonella and e-coli are examples of that. And some cutting boards are made with chemicals that fight bacteria. But experts say plain soap or detergent is just as effective as an anti-bacterial. The products that contain anti-bacterial agents probably don't cause any harm, but they probably aren't necessary to prevent the spread of bacterial infections. Beyond that, the best advice is to wash your hands frequently.