Tinctures are very concentrated liquid extracts of herbs and one of the most popular ways to take herbal medicine internally. You can simply dilute a dropper full or two of the tincture in a small amount of warm water and drink (which is wonderful if you don't want to fill your bladder before bed!). Tinctures use alcohol as the solvent, which extracts a greater amount of the medicinal constituents of the plant and preserves those constituents much longer than you can with dried herbs, or powder. Herbal tinctures are long-lasting--about 5 years--and preserve the freshness and potency of medicinal plants.
One of the reasons we find herbal tinctures to be so convenient is that they are an easy way to get herbs into your body, especially the ones that don't taste very good as a tea! Not to mention that they make it easy to take your health practices on the go; while at work, on vacation, etc. when making a tea is more difficult to do.