A solution in which the solvent is an alcohol is known as a tincture. For a solution to be considered a tincture, the alcohol content must be at least 40 percent ethanol. Typically, a tincture is a solution of ethanol and plant or animal material used for medicine.
Tinctures in medicine are made by adding an herb or another nonvolatile substance to alcohol in a container and leaving it sealed for two to three weeks. If plant matter is used in the solution, it is then filtered out. Tinctures are an advantage over aqueous solutions because some substances are more soluble in ethanol as opposed to water.