Prunes and kiwifruit are the two best fruits for constipation, with the strongest clinical evidence behind them. Both outperform fiber supplements in key measures like stool softness and reduced straining, and they work through different mechanisms, so the better choice depends on your body and preferences.
Why Prunes Work So Well
Prunes (dried plums) have been the go-to constipation remedy for generations, and the science backs it up. They contain roughly equal amounts of soluble and insoluble fiber, which is an unusually balanced ratio among fruits. Insoluble fiber adds bulk to stool and helps push it through the digestive tract. Soluble fiber draws water into the intestines, softening everything along the way.
But fiber alone doesn’t explain why prunes work better than other high-fiber foods. The real driver is sorbitol, a sugar alcohol that the body can’t fully absorb. Prunes contain about 15 grams of sorbitol per 100 grams, which is significantly more than most fruits. Sorbitol pulls water into the colon through osmosis, creating a natural laxative effect. When researchers at the University of Iowa tested prunes against an equivalent dose of fiber supplement, the prunes produced better results, and the team concluded the benefit came from components beyond fiber itself.
A standard effective dose in studies is about 100 grams per day, roughly 10 to 12 prunes.
Kiwifruit: The Gentler Option
Green kiwifruit has emerged as one of the most effective fruits for constipation, particularly for people who find prunes too aggressive or who experience bloating from dried fruit. In a clinical trial published in the American Journal of Gastroenterology, two kiwis per day matched both prunes and psyllium (a common fiber supplement) for increasing bowel movement frequency over four weeks. Kiwi also significantly improved stool consistency and reduced straining.
Kiwi works differently from prunes. It contains a protein-digesting enzyme called actinidin that speeds up how quickly food moves through your stomach. In animal studies, actinidin increased the rate of gastric emptying by 23 to 43 percent depending on the protein source. This faster upper-gut transit has a downstream effect on overall digestive speed. Kiwi also has a high water-holding capacity, meaning its fiber absorbs and retains water throughout the intestines, keeping stool soft without the intense osmotic pull that sorbitol creates.
For people who are sensitive to bloating or have irritable bowel symptoms, kiwi tends to be better tolerated than prunes because it’s lower in fermentable sugars.
Pears and Apples as Supporting Options
Pears are an underrated choice for constipation. They contain more sorbitol than apples, giving them a mild natural laxative effect similar to prunes but less concentrated. Pears also have a high fructose-to-glucose ratio, which means some of that fructose goes unabsorbed in the small intestine and draws water into the colon. This is the same osmotic mechanism that makes sorbitol effective, just at a lower intensity.
Apples work through a different pathway. They’re rich in pectin, a type of soluble fiber that gut bacteria ferment into short-chain fatty acids like butyrate. This fermentation lowers the pH in the colon, increases the water content of stool, and feeds beneficial bacteria that contribute to fecal bulk. Studies supplementing diets with apple pectin found higher butyrate production and softer stools compared to controls. Eating whole apples with the skin gives you both pectin and insoluble fiber, which is a better combination than apple juice alone.
Both fruits are helpful as everyday additions to your diet, but neither matches the potency of prunes or kiwi for active constipation relief.
How Quickly Fruits Relieve Constipation
Most people notice a change within a few days of increasing fruit intake, though the timeline varies. Sorbitol-rich fruits like prunes can produce results within 12 to 24 hours because their osmotic effect doesn’t depend on gut bacteria or slow fermentation. Fiber-rich fruits like apples work more gradually since their benefits come from bacterial fermentation and bulk formation, which takes longer to build up.
In the kiwi trial, measurable improvements in stool frequency appeared by the end of the first week, with the most significant changes during weeks three and four. If occasional constipation is the issue, a few days of higher fruit and fiber intake is often enough to get things moving again. For chronic constipation, consistent daily intake over several weeks tends to produce the best results.
Watch for Bloating With High-FODMAP Fruits
Several of the best fruits for constipation are also high in FODMAPs, the fermentable sugars that cause gas and bloating in sensitive individuals. Apples, pears, and prunes all fall into this category. They contain combinations of excess fructose, sorbitol, and other polyols that can ferment rapidly in the colon, producing gas before they produce relief.
If you have irritable bowel syndrome or tend to bloat easily, start with smaller portions and increase gradually. Green kiwifruit is the safest starting point for sensitive stomachs since it’s low in FODMAPs at normal serving sizes. With prunes, you might begin with four or five per day rather than jumping to the full 100-gram dose used in studies. Pears and apples are worth testing in small amounts, but if they worsen bloating during a flare-up, switch to kiwi instead.
How Much Fiber You Actually Need
Current dietary guidelines recommend 14 grams of fiber for every 1,000 calories you eat. For most adults, that works out to roughly 25 to 35 grams per day. The average American gets about half that amount, which is one reason constipation is so common.
Fruits alone won’t get you to that target. Two kiwis provide about 4 grams of fiber. Ten prunes deliver around 7 grams. A medium pear with the skin has roughly 6 grams, and a medium apple about 4.5 grams. These are meaningful contributions, but they work best alongside vegetables, whole grains, and legumes. Pairing a high-sorbitol fruit like prunes with adequate water intake amplifies the osmotic effect, since the sorbitol needs fluid to pull into the colon.
If you’re choosing one fruit to add to your routine specifically for constipation, prunes give you the most potent combination of fiber and sorbitol. If you want something gentler that you’ll actually enjoy eating every day, two green kiwis are equally effective by the clinical data and easier on the stomach.