Prune juice is a sweet, dark beverage made by extracting the soluble contents of dried plums (prunes) in hot water. Unlike most fruit juices, it isn’t squeezed from fresh fruit. Instead, dried plums are rehydrated and cooked in boiling water, and the resulting liquid is separated, clarified, and concentrated into the product you find on store shelves. It’s best known for its natural laxative effect, but it also delivers a surprisingly dense package of minerals.
How Prune Juice Is Made
The process starts with whole dried plums that are simmered in boiling water until they break down. The softened pulp is then pressed in a hydraulic press or spun in a high-speed centrifuge to separate the liquid from the solids. That extract goes through a settling or filtering step to clarify it, then gets concentrated with heat before canning or bottling. By U.S. standards, the finished product must contain at least 18.5 percent water-soluble solids extracted from the dried fruit.
This method is fundamentally different from how orange juice or apple juice is produced. Those start with fresh fruit and rely on mechanical squeezing. Prune juice is closer to a tea or a decoction: water pulls flavor, sugar, and nutrients out of the dried fruit over time. That’s why the flavor is so concentrated and the sugar content is relatively high.
Nutrition in One Cup
An 8-ounce glass of prune juice contains roughly 42 grams of sugar, which is comparable to many sodas. Most of that sugar occurs naturally in the dried plums, but it’s still worth noting if you’re watching your intake. The tradeoff is a strong mineral profile: one cup delivers about 707 milligrams of potassium (around 15 percent of the daily value for most adults) and 3 milligrams of iron, which covers a meaningful portion of daily needs, especially for people who don’t eat much red meat.
Fiber content lands at about 2.5 grams per cup. That’s modest compared to whole dried plums, which pack roughly 6.1 grams of fiber per 100 grams. Much of the insoluble fiber gets removed during the filtration step. What remains in the juice is mostly soluble fiber, particularly pectin, which dissolves into the water extract during cooking.
Why It Works as a Laxative
Prune juice owes its well-known digestive effect to three components working together: sorbitol, pectin, and polyphenols.
Sorbitol is a sugar alcohol that your small intestine absorbs slowly and incompletely. When it reaches your large intestine still partially undigested, it draws water into the colon through osmosis, softening stool and stimulating movement. Prune juice contains a significant amount of sorbitol compared to most other fruit juices, which is the primary reason it has a stronger laxative reputation than, say, apple juice.
Pectin, a type of soluble fiber, adds bulk to stool and feeds beneficial gut bacteria. The polyphenols in prune juice (primarily compounds called chlorogenic acids) appear to contribute as well, though their exact role in gut motility is less well understood than sorbitol’s. A randomized, placebo-controlled trial published in The American Journal of Gastroenterology found that prune juice improved subjective complaints and stool consistency in people with chronic constipation, with the researchers attributing the benefit to the combined action of all three components rather than any single one.
Prune Juice vs. Whole Prunes
If you’re choosing between the juice and the whole dried fruit, the biggest difference is fiber. Whole prunes retain all their insoluble fiber, which the juice loses during filtration. They also contain higher concentrations of phenolic compounds, roughly 184 milligrams per 100 grams, which may help slow glucose absorption in addition to supporting digestion.
Prune juice does have practical advantages, though. It’s easier to consume quickly, works well for people who dislike the texture of dried fruit, and is simpler to give to young children or older adults with chewing difficulties. For constipation relief specifically, both forms are effective. The juice delivers sorbitol and pectin efficiently, while whole prunes add the extra benefit of insoluble fiber. If your goal is overall nutrition, whole prunes are the better choice. If you need a quick, palatable option for occasional constipation, the juice does the job.
Using Prune Juice for Children
Prune juice is one of the go-to remedies pediatricians suggest for infant constipation. For babies younger than four months, Children’s Hospital of Philadelphia recommends a conservative approach: 1 ounce of prune juice mixed with 1 ounce of water, given once or twice a day. Apple and pear juice can be used the same way, but prune juice’s higher sorbitol content often makes it more effective.
For older babies and toddlers, slightly larger amounts are typically fine, but it’s worth starting small. The sorbitol that makes it effective can also cause cramping or loose stools if you overdo it. A couple of ounces diluted in water is a reasonable starting point for most toddlers.
Potential Downsides
The most common issue is digestive discomfort. Sorbitol can cause gas, bloating, and diarrhea when consumed in large amounts. People vary in their tolerance, but drinking more than one cup at a time is where most people start running into trouble. If you have irritable bowel syndrome or are sensitive to FODMAPs (a category of fermentable carbohydrates that includes sorbitol), prune juice may trigger symptoms even in smaller quantities.
The sugar content deserves attention too. At 42 grams per cup, prune juice is one of the sweeter options in the juice aisle. For people managing blood sugar levels, the combination of natural sugars and relatively low fiber means it can cause a faster glucose spike than eating whole prunes would. Diluting it with water or limiting yourself to a half-cup serving are straightforward ways to reduce that impact while still getting the digestive benefits.