[From Seidlitz, in Bohemia.] A natural mineral water ; also a powder having the same effect. The seidlitz owes its aperient property to the presence of Epsom salts (q.v.) and a little lime. Seidlitz powder has 2 drams of Rochelle salt and 40 grains of bicarbonate of soda in one paper, and 35 grains tartaric acid in another paper. When mixed these effervesce, and make a very pleasant draught.