Silver ions affect and kill fungi, viruses, all types of bacteria, and many parasites. The silver ions create a chemical and electrical mess both on the outside of the cell membrane and the inside.
Since most disease-causing bacteria are negatively charged, and the silver ions are positively charged, a natural attraction occurs. The silver searches for the disease-causing bacteria and immobilizes them. Silver ions do not affect the good intestinal bacteria, as those have a thicker cell wall.