First you need to define what a germ is. It is commonly assigned to bacteria, viruses and fungi all things that are in our bodies. Bacteria can be both good and bad for our body. Bacteria can get in our lungs and cause pneumonia or under out skin to cause infection. But good bacteria are found in our bodies too. Bacteria is found in our intestines and help us use nutrients in the food we eat and make waste from what is left over. That is why when you take certain antibacterial medicines to get rid of bad bacteria, it also affects the bacteria in our guts. Bacteria are also used to produce medicines and vaccines. Viruses are more commonly not as good for our bodies, such as those that cause colds, chicken pox, flu, etc. But many times once you have a virus you develop immunity to getting that virus again. The immunity is a virus that does not allow the same virus if entering the body anew to develop into a full-blown infection. Fungi are good in that, as mushrooms, they can provide nutrition. But some fungal infections can cause rashes and itching (athletes foot for example) that are irritating but rarely life threatening.