Narcotic, diuretic, sedative, antispasmodic, mydriatic. Belladonna is a most valuable plant in the treatment of eye diseases, Atropine, obtained during extraction, being its most important constituent on account of its power of dilating the pupil. Atropine will have this effect in whatever way used, whether internally, or injected under the skin, but when dropped into the eye, a much smaller quantity suffices, the tiny discs oculists using for this purpose, before testing their patient's sight for glasses, being made of gelatine with 1/50000 grain of Atropine in each, the entire disk only weighing 1/50 grain. Scarcely any operation on the eye can safely be performed without the aid of this valuable drug. It is a strong poison, the amount given internally being very minute, 1/200 to 1/100 grain. As an antidote to Opium, Atropine may be injected subcutaneously, and it has also been used in poisoning by Calabar bean and in Chloroform poisoning. It has no action on the voluntary muscles, but the nerve endings in involuntary muscles are paralysed by large doses, the paralysis finally affecting the central nervous system, causing excitement and delirium.
The various preparations of Belladonna have many uses. Locally applied, it lessens irritability and pain, and is used as a lotion, plaster or liniment in cases of neuralgia, gout, rheumatism and sciatica. As a drug, it specially affects the brain and the bladder. It is used to check excessive secretions and to allay inflammation and to check the sweating of phthisis and other exhausting diseases