Which preparation generally contains both oil and alcohol?

The correct choice, which is tincture, is a preparation that typically includes both alcohol and a plant extract or another active ingredient. Tinctures are made by soaking plant materials in alcohol or a mixture of alcohol and water, which allows the extraction of the active components of the plant. This combination not only helps to preserve the herbal constituents but also enhances the solubility of certain compounds that may not dissolve well in water alone.

In contrast, syrups primarily contain sugar and water, with no alcohol content, making them sweet, viscous solutions mainly used for administering medications that benefit from a palatable taste. Elixirs are sweetened hydroalcoholic solutions, but they contain less oil and are used primarily to dissolve and stabilize drugs. Emulsions are mixtures of two immiscible liquids, typically oil and water, stabilized by an emulsifier, but do not usually contain a significant amount of alcohol. Understanding these distinctions helps clarify why tinctures specifically contain both oil (in some formulations) and alcohol, making them unique in this aspect compared to the other preparations listed.