This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In prurigo, lichen, and chronic urticaria, disorders attended with violent itching, a lotion containing 1 to 3 dr. of dilute acid in 8 oz. of water often relieves. Pereira says that its internal administration is also efficacious.
Angina. For relaxed surfaces coated with tenacious mucus dilute sulphuric acid is an excellent cleansing astringent: hence it is inconstant use as a gargle (1 to 2 dr. in 8 oz. of infusion of roses) for relaxed uvula, etc.; in weaker proportion it is also suitable for scarlatinal throat. The addition of 2 dr. of alum to the gargle often greatly increases its value.
It is commonly said that for digestive disorders requiring an acid, hydrochloric is the best: to stimulate hepatic and intestinal secretion nitric acid is indicated, while the astringent effect of sulphuric is of special value in controlling sanguineous and other discharges.