Herbs are often suspended in liquid form in a base of water and some type of Alcohol. Ethanol or grain alcohol are often used because they are very stable, reasonably natural and improve the shelf life of the herbs. 25% alcohol being the most common.
To reduce the alcohol base of your tincture when you take them you can add your tincture to hot water and the alcohol will evaporate in just a few minutes.
Herbal tinctures are not always made using ethanol, though this is most common. Others include vinegar, glycerol & glycerite.