- For the song, see Gummiberry Juice (song)
The recipe is first known only by Grammi Gummi, until she later teaches it to Sunni Gummi. The juice is produced by adding six handfuls of red berries, then four orange berries, three purple berries, four blue berries, three green berries and one yellow berry. The recipe ends with the three-step-stir: First stir slowly to the right, then stir slowly to the left, then bang the pot to banish the bubbles. This apparently also stabilizes the magic concoction.
When she is coerced to demonstrate the recipe by Duke Igthorn, Grammi tricks him by leaving out the purple berries, which causes Igthorn and his Ogres to swell up and float like balloons when they drink it.
When it is drunk, Gummi Bears gain the ability to bounce at unusual heights for a limited amount of time; falling from heights which would normally be fatal to a Gummi, will only cause them to bounce like rubber. Ducks and other avians are granted identical bounciness, as evidenced in DuckTales. The ability to direct themselves while powered by the juice, such as bouncing along the ground, is not instinctive to Gummi Bears and must be learned, as the Barbic Gummies from Ursalia quickly find out.
Ogres and humans both gain super strength for a much more limited amount of time. Drinking too much Gummiberry Juice has unforeseen side effects on the consumer, and the abilities gained from drinking the juice can only be used by humans once per day. With this in mind, Cavin and Calla only drink the juice if asked to do so by the Gummi Bears, and if given a dose for later, they will only drink it in an emergency. Ogres are shown to be able to drink the juice and use its effects repeatedly.
Accordingly, Duke Igthorn arranges his tactics to attack in waves, to allow for his troupes to take maximum advantage of dosages. The juice can also serve as fuel for the various Gummi vehicles, such as the Gummi Flying Machine.
If the juice is produced inaccurately from the recipe, the results have adverse outcomes, though nothing fatal. In the episode "The Secret of the Juice", Grammi Gummi tries to teach Sunni Gummi for the first time how to make the juice. Grammi demonstrates the stir technique, but when it's Sunni's turn, it ends in disaster. She stirs the pot too vigorously and then bangs it too hard, causing the unstable juice to explode, covering Sunni, Grammi and the entire kitchen in juice. More than once, Grammi sabotages preparation of the juice while a prisoner of Duke Igthorn's in order to thwart him and escape, but by the final episode, "King Igthorn," he is no longer fooled by her tricks and reacts accordingly, such as forcing his minions to be test subjects.
Throughout the series, the juice is used as a major plot device, with the main recurring villain, Duke Igthorn, trying get a good supply of the juice, or the recipe to create mass amounts, in order to grant himself and the Ogres super strength so he can take over King Gregor's kingdom.