Lettuce, Lactuca virosa, is official in Hungary, Mexico, the Netherlands, Spain, and the U. S. Lactuca sativa is official in Mexico and Serbia. L. altissima is a suitable substitute for L. virosa; it is used by Aubergier, who has given the species comparative study.

A mild hypnotic said to contain traces of hyoscy-amine. Only the wild species of lettuce yield lactu-carium in any appreciable amount. The drug is an unreliable hypnotic, but 15-grain doses may be used as a substitute for opium, being effective in some cases. The average dose of the tincture is 30 minims. The syrup, in 1/2 to 2-drachm doses, is of some value in controlling irritable cough, more particularly in children.