Understanding the Side Effects of Eating Caju Fruit (Cashew Apple and Nut)

December 22, 2025 •

4 min read

The cashew tree produces both the familiar cashew nut and a fleshy, pear-shaped structure known as the cashew apple or caju fruit. While commercially sold cashews are safe, truly raw cashews and their shells contain a toxic compound, urushiol.

Quick Summary

This guide examines the distinct side effects linked to the edible cashew apple versus the commercially processed and unprocessed cashew nut. It details the dangers of urushiol in raw cashews and shells, potential allergic reactions, and digestive issues from overconsumption.

Key Points

Raw cashew nuts are toxic: The shell of raw cashews contains urushiol, a toxic oil that causes severe skin rashes and internal irritation.
Store-bought cashews are safe: All commercial cashews have been heat-processed to destroy the urushiol and are safe to eat.
Overconsumption can cause issues: Eating too many cashews, even if processed, can lead to weight gain and digestive problems like bloating.
Cashew allergies can be severe: Allergies to cashews are common and can trigger serious, life-threatening reactions like anaphylaxis.
The cashew apple is edible with caveats: The fleshy caju fruit is safe to eat but can have an astringent taste and may cause skin irritation in some sensitive individuals due to minor urushiol.

The Cashew: A Tale of Two Fruits

Many people are unaware that the popular cashew nut originates from a larger, fleshy, pear-shaped accessory fruit called the cashew apple or caju fruit. While the nut is prized globally, the apple is highly perishable and consumed locally in tropical regions. Understanding the side effects of eating caju fruit requires distinguishing between the risks associated with the nut and the apple.

The Hidden Danger of Raw Cashew Nuts

The most significant risk associated with the cashew plant lies in the unprocessed nut. The hard, grey shell encasing the cashew seed contains a toxic, caustic resin called urushiol, the same compound found in poison ivy. This is why consumers never encounter whole, unshelled cashews in stores. The commercial cashew nuts available for purchase are always shelled and have been heat-treated (steamed or roasted) to destroy the urushiol.

Eating a truly raw, unprocessed cashew nut can lead to serious health issues, including:

Skin irritation: Direct contact with the urushiol-containing shell can cause severe contact dermatitis, resulting in rashes, blistering, and intense itching.
Internal toxicity: Ingestion of the unprocessed nut can cause internal reactions, leading to stomach irritation and other systemic symptoms.
Allergic reactions: Exposure to urushiol can cause severe allergic reactions, especially in individuals sensitive to poison ivy, oak, or sumac.

Side Effects of Commercially Processed Cashew Nuts

Even commercially processed cashews, which are free from urushiol, can cause side effects, typically linked to overconsumption or pre-existing conditions.

Weight gain: Cashew nuts are calorie-dense, and consuming them in large quantities can lead to unwanted weight gain. A healthy portion is typically a small handful.
Digestive issues: For some individuals, especially those with sensitive digestive systems, eating too many cashews can cause gastrointestinal discomfort, such as bloating, gas, and constipation.
Allergies: Cashew allergies are a common tree nut allergy and can range from mild to life-threatening. Symptoms can include hives, swelling, abdominal pain, and in severe cases, anaphylaxis. Cross-reactivity with pistachios is also common.
Drug interactions: The magnesium content in cashews can interact with certain medications, including quinolone antibiotics. It can bind to the medication and prevent its proper absorption.

The Potential Issues with the Cashew Apple

The cashew apple itself is edible and rich in vitamin C and antioxidants, but it is not without its own set of potential drawbacks.

Astringent taste: The fruit contains tannins, which can give it a sharp, astringent flavor that many people find unpalatable. Slicing the fruit thinly and adding salt can help reduce the astringency.
Urushiol on the skin: While the apple is generally safe, the skin can contain minor amounts of urushiol. People with sensitivity to poison ivy may experience a mild rash or skin irritation from handling the fruit.
Digestive discomfort: The high fiber content in the cashew apple can cause digestive upset if consumed in excessive amounts, particularly for those not accustomed to it.

Safe Preparation and Consumption of Cashew Apple

For those who have access to the fresh fruit and wish to enjoy it, proper preparation can mitigate some of its potential downsides.

Select ripe fruit: Ripe cashew apples have a sweeter taste and are less astringent than underripe ones.
Wash and handle with care: Wash the fruit thoroughly before handling. If you have a known poison ivy allergy, wearing gloves is a prudent precaution.
Reduce astringency: To minimize the tart, astringent flavor, slice the fruit thinly and sprinkle it with salt before chilling.
Consider alternative uses: The cashew apple is often used to make juices, jams, and fermented beverages, which can make it more palatable.

Comparison: Raw vs. Processed Cashew Nuts


Feature	Raw Cashew Nut (Unprocessed)	Commercially Processed Cashew Nut
Urushiol Content	High. Contains toxic urushiol in the shell and on the surface.	None. Toxic urushiol is removed during steaming/roasting.
Safety for Consumption	Highly Toxic. Can cause severe internal and external reactions if ingested.	Safe for Consumption. Free from the toxic shell and urushiol.
Availability	Not available to consumers. Requires specialized industrial processing.	Widely available in stores as 'raw' (steamed), roasted, or salted.
Preparation	Do Not Attempt at Home. Industrial heating and shelling are required.	No additional processing is necessary for safety before eating.

Conclusion

While commercially available cashew nuts and the edible cashew apple are generally safe for consumption in moderation, understanding the potential risks is crucial. The primary hazard lies in the unprocessed cashew nut and its urushiol-containing shell, which is why proper industrial heat-treatment is essential before they reach consumers. Individuals with cashew allergies or those susceptible to digestive issues should be mindful of their intake. The cashew apple, though less common in many markets, is edible but requires proper preparation to address its astringency. By being aware of these aspects, consumers can enjoy the nutritional benefits of the caju fruit safely.

For more information on processing and safety, see the CDC's report on dermatitis related to cashew nut handling.

Frequently Asked Questions

No, the caju fruit or cashew apple is not poisonous and is edible. It is often eaten fresh or used in juices and jams in tropical regions. However, its skin can contain minor traces of urushiol, which may cause a mild reaction in individuals highly sensitive to poison ivy.

Urushiol is a toxic, oily substance found in the cashew nut's shell and is also present in poison ivy and poison oak. It causes a severe allergic skin rash (contact dermatitis) and can cause serious internal reactions if ingested in its unprocessed form.

Commercially labeled 'raw' cashews are not truly raw. They have been steamed or roasted to remove the toxic urushiol from their shells, making them safe for consumption. Truly raw cashews with their shells are never sold to consumers.

Yes, overconsumption of cashews can lead to digestive issues such as bloating, constipation, and gas. This is due to their high fat and fiber content, which can be difficult for some individuals to digest in large quantities.

Symptoms of a cashew allergy can range from mild (hives, itching) to severe (swelling, breathing difficulty, anaphylaxis). It is crucial to seek a proper diagnosis from an allergist, especially if you experience any adverse reactions after consumption.

The primary risk from the cashew nut comes from the highly toxic urushiol in its shell, which is removed during commercial processing. The cashew apple, while edible, has a naturally astringent taste and a small amount of urushiol on its skin that can affect sensitive individuals.

Yes, cashews contain magnesium, which can interact with certain medications, including specific types of antibiotics. This interaction can affect the drug's absorption. Consult a healthcare provider if you have concerns about drug interactions.