Hawaiian Citron

Lemon juice is widely known as a diuretic, antiscorbutic, astringent, and febrifuge. In Italy, the sweetened juice is given to relieve gingivitis, stomatitis, and inflammation of the tongue. Lemon juice in hot water is widely known as a daily laxative and preventive of the common cold. Concentrated lemon juice or lemon juice and honey, or lemon juice with salt or ginger, is one of the best cold remedies. It was the juice of the Mediterranean sweet lemon, not the lime, that was carried aboard British sailing ships of the 18th Century to prevent scurvy, though the sailors became known as "limeys".
Oil expressed from lemon seeds is employed medicinally. The root decoction is taken as a treatment for fever in Cuba and for gonorrhea in West Africa. An infusion of the bark or of the peel of the fruit is given to relieve colic.
(Morton, J. 1987. Fruits of warm climates.)

Rough Lemons are used just like the common lemon. Slices of Rough Lemon are served as a garnish on fish or meat or with iced or hot tea, to be squeezed for the flavorful juice. In Colombia, lemon soup is made by adding slices of lemon to dry bread roll that has been sauted in shortening until soft and then sieved. Sugar and a cup of wine are added and the mixture brought to a boil, and then served.
Lemon juice, fresh, canned, concentrated and frozen, or dehydrated and powdered, is primarily used for lemonade, in carbonated beverages, or other drinks. It is also used for making pies and tarts, as a flavoring for cakes, cookies, cake icings, puddings, sherbet, confectionery, preserves and pharmaceutical products. A few drops of lemon juice, added to cream before whipping, gives stability to the whipped cream.
Lemon peel can be candied at home and is preserved in brine and supplied to manufacturers of confectionery and baked goods. It is the source of lemon oil, pectin and citric acid. Lemon oil, often with terpenes and sesquiterpenes removed, is added to frozen or otherwise processed lemon juice to enrich the flavor. It is much employed as a flavoring for hard candies.
(Morton, J. 1987. Fruits of warm climates.)