Dandelion is a perennial with a thick taproot. The saw-toothed leaves form a rosette at the base of the plant. Solitary, bright yellow flowers appear from spring to autumn. Ribbed fruits bearing tufts of fine, white hairs follow flowers. Dandelion is well known as a garden weed. Dandelion is also a rich source of vitamins and minerals. Dandelion is commonly used as a food. The leaves are used in salads and teas , while the roots are often 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 countries, dandelion is considered a blood purifier and is used for ailments such as eczema and cancer. Dandelion has also been used historically to treat poor digestion.