Do prunes have a lot of acid? An expert look at pH, digestion, and health

January 8, 2026 •

4 min read

With a typical pH range of 3.6 to 4.2, prunes are considered moderately acidic, a fact that often surprises those who rely on them for digestive relief. This guide dives into the science behind prune acidity and explains why their effects on digestion are more nuanced than their pH alone suggests.

Quick Summary

Prunes are moderately acidic with a pH of 3.6-4.2, containing malic, quinic, and chlorogenic acids. Despite this, their high fiber and sorbitol content, along with an alkalizing effect on the body, makes them generally tolerable for individuals with acid reflux.

Key Points

Moderate Acidity: Prunes have a pH of 3.6-4.2, making them moderately acidic, similar to apples and peaches.
Alkalizing Effect: Despite their intrinsic acidity, prunes have an overall alkalizing effect on the body after digestion, which is beneficial.
GERD Friendly: Prunes are generally considered a safe food for those with acid reflux due to their fiber content and low potential to trigger symptoms when eaten in moderation.
Digestive Aid: Their primary digestive benefit comes from high fiber and sorbitol, which promote regular bowel movements, not their acidity.
Moderation is Key: Overconsumption can lead to gas, bloating, or diarrhea due to high fiber and sorbitol, not the fruit's pH.
Nutrient Powerhouse: Prunes are packed with vitamins (K, A), minerals (potassium), and antioxidants that support bone and heart health.

What is the Acidity of Prunes?

To understand the acidity of prunes, it's important to know about the pH scale. This scale runs from 0 to 14, where a pH of less than 7 is acidic, a pH of 7 is neutral, and a pH greater than 7 is alkaline. According to food data and sources like Verywell Health, prunes typically have a pH value between 3.6 and 3.9, which places them in the moderately acidic range.

The acidity in prunes comes from naturally occurring organic acids. The most notable are malic and quinic acids, which are responsible for the fruit's tangy flavor. Additionally, prunes contain phenolic compounds, including neochlorogenic and chlorogenic acids, which contribute to their unique health benefits. While their pH is acidic, it is significantly less so than highly acidic fruits like lemons (pH 2.0-2.6) or grapefruits (pH 3.0-3.75).

Prune Acidity vs. Fresh Plum Acidity

It is also worth noting that the drying process concentrates both the sugars and acids in the fruit. This means that while fresh plums are also acidic (pH 2.8-3.4), the flavor and composition of a prune are distinct due to this concentration. The drying process, however, does not make prunes prohibitively acidic for most people.

Prunes vs. Other Fruits: A Comparison

For a better perspective on where prunes stand, here is a comparison of their pH with other common fruits:


Fruit	pH Range	Acidity Level
Lemon Juice	2.0–2.6	Highly Acidic
Grapefruit	3.0–3.75	Highly Acidic
Plums (fresh)	2.8–3.4	Highly Acidic
Prunes (dried)	3.6–4.2	Moderately Acidic
Apples	3.3–4.0	Moderately Acidic
Peaches	3.3–4.05	Moderately Acidic
Bananas	4.5–5.2	Low Acidity

As the table shows, prunes fall within a similar acidity range to many other commonly consumed fruits. This level is a natural characteristic and not a cause for concern for the average person.

How Prune Acidity Affects Digestion

The most important takeaway is that a food's inherent pH does not always directly correlate with its effects on the body. This is a common misconception, particularly concerning conditions like acid reflux or GERD. In fact, many individuals find that prunes are well-tolerated and even beneficial for their digestive system. The reason lies in other compounds found in the fruit, rather than its acidity.

The Prune Paradox: Acidic but Often Tolerable

For people with acid reflux or GERD, triggers are highly individual. While some highly acidic foods like citrus fruits and tomatoes are often advised against, prunes are frequently considered safe and can even be beneficial. This is primarily due to their high fiber content. According to Everyday Health, the soluble and insoluble fiber in prunes can help regulate digestion and promote better gut function, which can indirectly reduce the risk of reflux.

Furthermore, the fiber can help you feel full, reducing the likelihood of overeating, which is a known trigger for acid reflux. By consuming prunes in moderation and as a snack rather than with large meals, many people with GERD can enjoy their benefits without issue.

The Key Digestive Drivers: Sorbitol and Fiber

Beyond their intrinsic acidity, prunes are renowned for their gentle laxative effects, which are not caused by their acid content. Instead, these effects are driven by their sorbitol and high fiber content.

Sorbitol: This natural sugar alcohol draws water into the large intestine. This softens the stool and stimulates bowel movements, making it an effective remedy for constipation.
Fiber: Prunes are an excellent source of both soluble and insoluble fiber. Insoluble fiber adds bulk to stool, while soluble fiber forms a gel-like substance that aids in its passage through the digestive tract. Together, they promote regular bowel movements and support a healthy gut microbiome by acting as a prebiotic.

Potential Side Effects and Considerations

While prune acidity is generally not an issue for most people, overconsumption can lead to other digestive discomforts. This is more related to the high fiber and sorbitol content than the fruit's pH.

Gas and Bloating: Consuming too many prunes, especially if you're not used to a high-fiber diet, can lead to gas and bloating. Introducing them slowly into your diet can help your system adjust.
Diarrhea: In larger quantities, the combination of sorbitol and fiber can cause diarrhea, especially in sensitive individuals. It's best to stick to recommended serving sizes, typically 4-5 prunes per day, to avoid this.

Incorporating Prunes into Your Diet Safely

To enjoy the benefits of prunes while minimizing any potential digestive issues, follow these simple tips:

Start Slow: If you are new to prunes, begin with a small portion (1-2 prunes) and gradually increase your intake to let your body adjust.
Stay Hydrated: Drinking plenty of water is essential when increasing fiber intake, as it helps the fiber move smoothly through your digestive system.
Mix it Up: Don't just eat them plain. Chop and add prunes to your oatmeal, yogurt, or salads for a natural sweetness boost.
Try Prune Juice: If whole prunes cause discomfort, a small glass of 100% prune juice can still provide beneficial sorbitol and nutrients.

Conclusion

Ultimately, the question, "Do prunes have a lot of acid?" is more complex than a simple yes or no. While prunes are moderately acidic in terms of pH, their overall impact on the body's digestive system is often alkalizing and therapeutic due to their rich fiber and sorbitol content. For most individuals, including those with acid reflux, prunes are a safe and healthy addition to a balanced diet, provided they are consumed in moderation. Their primary role in aiding digestion is through their natural laxative properties, not their mild acidity, making them a functional food that supports gut health effectively. For those managing acid reflux, paying attention to portion size and timing, as with any food, is key to enjoying this nutrient-dense fruit. You can find more information about the efficacy of prunes for healthy digestion on the Sunsweet website.(https://www.sunsweet.com/articles/demystifying-the-efficacy-of-prunes-how-and-why-prunes-are-your-gut-s-best-friend)

Frequently Asked Questions

Yes, prunes are an acidic food with a pH range of 3.6 to 4.2. However, this is considered a moderate level of acidity, and their impact on your body can be alkalizing due to other nutritional factors.

For many people with acid reflux or GERD, prunes are safe to eat. Their high fiber content can aid digestion and prevent overeating. Portion control and eating them as a snack, rather than with a large meal, is recommended.

Prune juice has a pH in a similar range to whole prunes, making it moderately acidic. However, like the fruit, its digestive benefits primarily come from sorbitol and not its pH level.

The laxative effect of prunes is not due to their acidity. It is caused by their high content of sorbitol, a sugar alcohol that draws water into the colon, and both soluble and insoluble fiber that add bulk to stool.

Prunes contain organic acids such as malic, quinic, neochlorogenic, and chlorogenic acids. These contribute to their flavor and antioxidant properties.

Prunes do not typically cause stomach issues due to their acidity. Any discomfort, such as gas or bloating, is more likely a side effect of overconsuming their high fiber and sorbitol content, especially for those unaccustomed to it.

While the drying process concentrates the sugars and acids, the pH of dried prunes (3.6-4.2) and fresh plums (2.8-3.4) are in a similar acidic range, with plums sometimes being more acidic. The difference is not significant enough to cause issues for most people.

Despite their initial pH, many fruits and vegetables, including prunes, are considered alkalizing to the body once metabolized. They can help balance the effects of acid-forming foods.

For those concerned about acidity, eating prunes in moderation is key. You can also pair them with alkaline-forming foods like nuts, vegetables, or whole grains.