Dandelion is commonly used as a food. The leaves are used in salads and teas, while the roots are sometimes used as a coffee substitute. Dandelion leaves and roots have been used for hundreds of years to treat liver, gallbladder, kidney, and joint problems. In some traditions, dandelion is considered a blood purifier and is used for conditions as varied as eczema and cancer. As is the case today, dandelion leaves have also been used historically to treat water retention.