This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
Water is described by the pharmacopeia as potable water in its purest obtainable state. Water used for medicines should be sterile; It is preferable to use:
Distilled water is described as a colorless, limpid liquid, without odor or taste, and perfectly neutral to litmus paper. For some purposes (in making solutions of salvarsan, for example), it is essential that it be freshly distilled. Ordinary distilled water frequently is not sterile.
The official medicated waters are aqueous solutions of volatile substances. The aromatic waters are saturated solutions of volatile oils. They are used as vehicles for the more active, water-soluble drugs. For preparations included in this list see:
Aqua Ammoniae, under Ammonia. Aqua Camphorae, under Camphora.
Aqua Chloroformi, under Chloroformum.
Aqua Cinnamomi, under Cinnamomum.
See Under Hydrogenii Dioxidum.
Aqua Menthae Piperitae, under Mentha Piperita.
Aqua Rosae, under Rosa.