Lactuca sativa longifolia
Herb: Cos Lettuce
Latin name: Lactuca sativa longifolia
Medicinal use of Cos Lettuce:The whole plant is rich in a milky sap that flows freely from any wounds. This hardens and dries when in contact with the air. The sap contains "lactucarium", which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets, nor is it addictive. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower. It is collected commercially by cutting the heads of the plants and scraping the juice into china vessels several times a day until the plant is exhausted. The cultivated lettuce does not contain as much lactucarium as the wild species, most being produced when the plant is in flower. An infusion of the fresh or dried flowering plant can also be used. The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness whilst excess causes restlessness and overdoses can cause death through cardiac paralysis. Some physicians believe that any effects of this medicine are caused by the mind of the patient rather than by the medicine. The sap has also been applied externally in the treatment of warts. The seed is anodyne and galactogogue. Lettuce has acquired a folk reputation as an anaphrodisiac, anodyne, carminative, diuretic, emollient, febrifuge, hypoglycaemic, hypnotic, narcotic, parasiticide and sedative.
Description of the plant:
Habitat of the herb:Not known in the wild.
Edible parts of Cos Lettuce:Leaves - raw or cooked. A mild slightly sweet flavour with a crisp texture, lettuce is a very commonly used salad leaf and can also be cooked as a potherb or be added to soups etc. A nutritional analysis is available. Seed - sprouted and used in salads or sandwiches. An edible oil is obtained from the seed. The seed is very small, extraction of the oil on any scale would not be very feasible.
Other uses of the herb:Parasiticide. No further details are given, but it is probably the sap of flowering plants that is used. The seed is said to be used to make hair grow on scar tissue.
Propagation of Cos Lettuce:Seed - sow a small quantity of seed in situ every 2 or 3 weeks from March (with protection in cooler areas) to June and make another sowing in August/September for a winter/spring crop. Only just cover the seed. Germination is usually rapid and good, thin the plants if necessary, these thinnings can be transplanted to produce a slightly later crop (but they will need to be well watered in dry weather). More certain winter crops can be obtained by sowing in a frame in September/October and again in January/February.
Cultivation of the herb:Not known in the wild.
Known hazards of Lactuca sativa longifolia:The mature plant is mildly toxic.
Plant information taken from the Plants For A Future.