They absorb nutrients from other organisms, both dead and living. In this way they are an extreme help to the environment. Fungi continue the cycle of life by breaking down the dead organisms into nutrients that can be used by the new. Some fungi are parasites that attach to living plants or animals, and others cooperate with trees and shrubs to exchange essential nutrients. Many plants could not exist without the fungi that live on or near them.
Fungi also have medicinal uses.
They provide drugs such as penicillin and other antibiotics. However, they can also be very poisonous. There have been many stories of people thinking mushrooms were safe to eat, and then getting very ill or even dying from them. Some cause various diseases in plants, animals, and humans. Ringworm and athlete's foot are just some examples of them.