The flowers and leaves are added to salads.
Viola tricolor is used the same way as the Blue or Sweet-scented Violet, Viola odorata. Used as an infusion, strong decoction and syrup. Medicinal and edible, the flowers and leaves of viola are made into a syrup used in alternative medicine mainly for respiratory ailments associated with congestion, coughing, and sore throat. Tea made from the leaves is used to treat digestive disorders and new research has detected the presence of a glycoside of salicylic acid (natural aspirin) which substantiates its use for centuries as a medicinal remedy for headache, body pains and as a sedative. The plants constituents include eugenol, ferulic-acid, kaempferol, quercetin, and scopoletin.
Used externally the leaf infusion reduces swelling and soothes irritations. As a bath additive the leaves are soothing to the skin and the aroma is very relaxing. The leaves are used in cooling plasters, oyles and comfortable cataplasms or poultices. They are an old popular remedy for bruises. The glucosidal principles contained in the leaves have not yet been fully investigated, but would appear to have distinct antiseptic properties. Preparations of fresh leaves have been used both internally and externally in the treatment of cancer. From other sources it is stated that leaves have been used with benefit to allay the pain in cancerous growths, especially in the throat, which no other treatment relieved, and several reputed cures have been recorded.
An infusion of the leaves in boiling water (1 in 5) has been administered in doses of 1 to 2 fluid ounces. The infusion is generally drunk cold and is made as follows: Take 2½ oz. of leaves, freshly picked. Wash them clean in cold water and place them in a stone jar and pour over them 1 pint of boiling water. Tie the jar down and let it stand for twelve hours, till the water is green. Then strain off the liquid into a well-stoppered bottle and the tea is ready for drinking cold at intervals of every two hours during the day, taking a wineglassful at a time till the whole has been consumed. A syrup of the petals and a liquid extract of the fresh leaves are also used, the latter taken in teaspoonful doses, or rubbed in locally. The fresh leaves are also prepared as a compress for local application.