Chervil is not widely used as a medicinal herb, though it is sometimes employed as a 'spring tonic' for cleansing the liver and kidneys, is a good remedy for settling the digestion and is said to be of value in treating poor memory and mental depression. The fresh plant, harvested just before flowering, is digestive, diuretic, expectorant, poultice and stimulant. The juice is used in the treatment of dropsy, arthritis and chronic skin ailments. The bruised leaves are used as a poultice for slow-healing wounds and a warm poultice is applied to painful joints. An infusion of the fresh leaves is also used as an eyewash to treat sore or inflamed eyes. Source: https://pfaf.org/
Find more about this plant on Wikipedia.