An example:
Gin alone can be called juice. Gin, when mixed with tonic water or whatever, is then called a Gin and Tonic, losing the juice descriptor.

courtesy of Byron C. Howes (bch@ecsvax.uncecs.edu)

I cannot sing juice's praises enough. Here are just some benefits of juice:

• It gives us all of vegetable's nutrients and vitamins. Vegetables in their raw form do not impart us with all their minerals because they are bound by cellulose, which humans cannot break down. You can break down cellulose by cooking the vegetables but then you kill nutrients. Juicing rids the vegetable of the cellulose but not the good stuff.
• Fruit juices act primarily as cleansers to detoxify the blood, to purify the organs.
• Vegetable juices have more of a tonic effect that heals, stabilizes and builds the body.
• They are potent elixirs which will push you through your day with their synergistic power.
• Juices imbibe us with a dose of living foods electrochemical energy.
• They help you cut thousands of calories and quench your appetite besides, because they contain so much concentrated nourishment.
• In saying all this, store bought bottled juice is dead. You may as well being drinking soft drink. Which makes American children fat.

  And, nutrients are great, (as in the case of veges), but to serve our bodies they must be able to get into our cells. Juice allows this immediately.

  invest in a juicer, baby!

Juice (?), n. [OE. juse, F.jus broth, gravy, juice, L. jus; akin to Skr. ysha.]

The characteristic fluid of any vegetable or animal substance; the sap or part which can be expressed from fruit, etc.; the fluid part which separates from meat in cooking.

An animal whose juices are unsound. Arbuthnot.

The juice of July flowers. B. Jonson.

The juice of Egypt's grape. Shak.

Letters which Edward Digby wrote in lemon juice. Macaulay.

Cold water draws the juice of meat. Mrs. Whitney.

© Webster 1913.

Juice (?), v. t.

To moisten; to wet.

Fuller.

© Webster 1913.