A tincture is typically an extract of plant, animal or mineral material dissolved in ethyl alcohol (ethanol). Solvent concentrations of 10–25% are common, but may run as high as 90%. In chemistry, a tincture is a solution that has ethanol as its solvent. In herbal medicine, alcoholic tinctures are made with various ethanol concentrations, 10-20% being the most common. Tinctures are often made of a combination of ethyl alcohol and water as solvents, each dissolving constituents the other is unable to, or weaker at. Varying their proportions can also produce different levels of constituents in the final extraction. As an antimicrobial, alcohol also acts as a preservative. Ethanol tinctures are used in preparations for use, such as health, personal care, creams and ointments.