A tincture is typically an alcoholic extract of plant or animal material or solution of such or of a low volatility substance (such as iodine and mercurochrome). To qualify as an alcoholic tincture, the extract should have an ethanol percentage of at least 40–60% or 80–120 proof. Sometimes even a 90% or 180 proof tincture is achieved. In herbal medicine, alcoholic tinctures are made with various concentrations of ethanol, 25% being the most common. Other concentrations include 45% and 90%.
Herbal tinctures are not always made using ethanol as the solvent, though this is most commonly the case. Other solvents include vinegar, glycerol, ether and propylene glycol, not all of which can be used for internal consumption. Ethanol has the advantage of being an excellent solvent for both acidic and basic (alkaline) constituents.
Glycerine can also be used, but when used in tincturing fashion is generally a poorer solvent. Vinegar, being acidic, is a better solvent for obtaining alkaloids but a poorer solvent for acidic components. For individuals who chose not to imbibe alcohol, non-alcoholic e,g., (glycerite) extracts offer an alternative for preparations meant to be taken internally.
Alcohol cannot be subjected to high temperatures, so its use is considered a self-limiting 'non-critical' passive methodology. Glycerol, utilized in a non-critical fashion as it was in early Eclectic medicine studies, is typically seen as inferior to alcohol, whereas if glycerol is subjected to an innovative synchronous serialized methodology now being acknowledged in the industry, the extractive potential of glycerol use this way is quite astounding and far exceeds the weak extractive potential for a tincturing methodology. Therefore, newer glycerite products are showing great promise and even rivaling alcoholic tinctures in many ways. 
Some solutions of volatile or nonvolatile substances are traditionally called spirits, regardless of whether obtained by distillation or not and whether or not they even contain alcohol. In chemistry, a tincture is a solution that has alcohol as its solvent.
General method of preparation
- Herbs are put in a container and a spirit of 40% or more ethanol is added, 80 proof Vodka or 190 proof Everclear, for example.
- The jar is left to stand for 2–3 weeks and shaken occasionally in order to maximize extraction.
More accurate measuring can be done by combining 1 part herbs with a water-ethanol mixture of 2–10 parts, depending on the herb itself. For most tinctures, however, 1 part water to 5 parts ethanol is typical.
Some examples that were formerly common in medicine include:
- Tincture of Cannabis sativa
- Tincture of Benzoin
- Tincture of cannabis, (Green Dragon)
- Tincture of cantharides
- Tincture of Castoreum
- Tincture of ferric citrochloride, a chelate of citric acid and Iron(III) chloride
- Tincture of green soap, which classically contains lavender oil
- Tincture of guaiac gum
- Tincture of iodine
- Tincture of opium, (laudanum)
- Camphorated opium tincture (paregoric)
- Tincture of Pennyroyal
- Warburg's Tincture, ("Tinctura Antiperiodica" or "Antiperiodic Tincture", a 19th-century antipyretic
Examples of spirits include:
- Spirit of ammonia (spirits of hartshorn)
- Spirit of camphor
- Spirit of ether, a solution of diethyl ether in alcohol
- "Spirit of Mindererus", ammonium acetate in alcohol
- "Spirit of nitre" is not a spirit in this sense, but an old name for nitric acid (but "sweet spirit of nitre" was ethyl nitrite)
- Similarly "spirit(s) of salt" actually meant hydrochloric acid. The concentrated, fuming, 35% acid is still sold under this name in the UK, for use as a drain-cleaning fluid.
- "Spirit of vinegar" is an antiquated term for glacial acetic acid
- "Spirit of vitriol" is an antiquated term for sulfuric acid
- "Spirit of wine" or "spirits of wine" is an old term for alcohol (especially food grade alcohol derived from the distillation of wine)
- "Spirit of wood" referred to methanol, often derived from the destructive distillation of wood
Ethanol is able to dissolve substances which are less soluble in water, while at the same time the water content can dissolve the substances less soluble in ethanol. One can sometimes vary the proportion of ethanol and water to produce tinctures with different characteristics due to the distinct solvent properties of these two. Tincture of calendula is commonly tinctured at either 25% or 90% ethanol. The alcohol content also acts as a preservative.
Ethanol has a tendency to denature some organic compounds, rendering them so changed as to be ineffective. This is one reason why ethanol is an antimicrobial. This tendency can also have undesirable effects when extracting botanical constituents, for instance, polysaccharides. Certain other constituents, common among them proteins, can become irreversibly denatured, or "pickled" in a manner of speaking. Also, extracted for highly complex aromatic components are denatured by alcohol's intrinsic cleaving action upon an aromatic's complex structure into simpler inert-rendered compounds. A basic tenet of organic chemistry teaches that anytime a biologically viable component is denatured, it will reduce or negate its prior biological viability. This fact must be considered by the clinician and/or consumer from both the standpoint of efficacy and dosage when choosing ethanol-based botanical tinctures.
Although ether and propylene glycol based tinctures are not suitable for internal consumption, they are used in preparations such as personal care cremes and ointments.
- Nalewka - a traditional Polish category of alcoholic tincture.
- Infusion - a water or oil based extract with similar historical uses to a tincture.
- Elixir - A pharmaceutical preparation containing an active ingredient that is dissolved in a solution containing some percentage of ethyl alcohol.
- Topical - categorization of topical skin preparation options
- Groot Handboek Geneeskrachtige Planten by Geert Verhelst
- The Pharmacopoeia of the United States, 1850 ed.