Nutrition Diet: What are the symptoms of rhubarb poisoning?

Despite its popularity in pies and crumbles, a little-known fact is that rhubarb leaves contain high concentrations of oxalic acid, a toxic compound. This is why it is crucial to understand what are the symptoms of rhubarb poisoning and how to avoid it entirely.

Quick Summary

Rhubarb poisoning results from ingesting the plant's leaves, which contain toxic oxalic acid. Symptoms range from mild gastrointestinal upset to serious complications like kidney damage.

Key Points

• Oxalic Acid: Rhubarb leaves are toxic due to high concentrations of oxalic acid, which can cause poisoning if ingested.

• Initial Symptoms: Mild rhubarb poisoning often presents as a burning sensation and swelling in the mouth and throat, along with nausea, vomiting, and diarrhea.

• Systemic Effects: Severe poisoning can lead to kidney stones, kidney damage, difficulty breathing, seizures, and in very rare cases, death.

• Stalks vs. Leaves: The rhubarb stalks are safe for consumption, but the leaves must always be removed and discarded before cooking or eating.

• Emergency Response: In case of accidental ingestion, immediately contact a poison control center and seek emergency medical help.

• Pet Safety: Be extra cautious with pets, as they are more vulnerable to poisoning from chewing on rhubarb leaves.

The Science Behind Rhubarb Poisoning

While the stalks of the rhubarb plant are a delicious and popular ingredient, the leaves are highly toxic and should never be consumed. The danger stems from a naturally occurring compound called oxalic acid, which is present in higher concentrations in the leaves. Oxalic acid and its salts, known as oxalates, are what trigger the adverse health effects associated with rhubarb poisoning. When these oxalates are ingested, they bind with calcium in the body. This process can cause an acute drop in calcium levels (hypocalcemia), leading to systemic problems. Furthermore, the resulting calcium oxalate crystals can accumulate in the kidneys, potentially leading to renal damage or even kidney failure in severe cases.

Common and Mild Symptoms of Rhubarb Poisoning

For individuals who have ingested a small amount of rhubarb leaves, symptoms are typically mild and localized, though still unpleasant. Many of these initial symptoms are a direct result of the oxalic acid irritating the sensitive tissues of the mouth, throat, and gastrointestinal tract.

• Oral Irritation: A burning sensation, redness, and swelling in the mouth, tongue, and throat are common immediate reactions. Blisters may also form in severe cases.

• Gastrointestinal Distress: Nausea, vomiting, diarrhea, and stomach pain are classic signs of poisoning.

• Weakness and Drowsiness: The body's overall systemic response to the toxin can cause a general feeling of fatigue or weakness.

• Hoarse Voice: Swelling in the throat can lead to a hoarse voice or difficulty speaking normally.

Severe and Systemic Symptoms

In cases of larger-scale ingestion, the poisoning can lead to more serious and life-threatening complications. When a significant amount of oxalates are absorbed into the bloodstream, they can disrupt the body's normal functions, leading to severe illness.

• Kidney Failure: The most critical risk from oxalic acid poisoning is acute kidney failure. The formation of calcium oxalate crystals in the kidneys can block the tubules, impairing kidney function. This can manifest as flank and back pain, and can be detected by red-colored urine.

• Breathing Difficulties: Swelling in the throat can become severe enough to obstruct breathing, requiring immediate medical intervention.

• Seizures and Tremors: The drop in blood calcium can disrupt neurological function, causing tremors, muscle twitches, or even seizures.

• Coma: In extreme cases, a significant dose of oxalic acid can lead to a state of unconsciousness and lack of responsiveness.

Safe Handling and Prevention

Prevention is the best approach to avoiding rhubarb poisoning. Since only the stalks are edible, knowing how to properly prepare and handle rhubarb is essential for anyone who gardens or cooks with the plant.

1. Discard Leaves Immediately: When harvesting rhubarb, cut and discard the leaves away from the edible stalks. Do this immediately to prevent accidental consumption.
2. Dispose of Leaves Safely: Rhubarb leaves can be safely composted, as the oxalic acid breaks down during the decomposition process. However, ensure that the leaves are not accessible to pets or children during this time.
3. Wash Hands Thoroughly: Always wash your hands after handling rhubarb leaves to avoid contact dermatitis or transferring the toxin to other foods.
4. Educate Children and Pets: Teach children not to touch or eat any part of the rhubarb plant without supervision. Keep pets away from rhubarb patches, as they are also susceptible to poisoning.

What to Do in a Rhubarb Poisoning Emergency

If you or someone you know has ingested rhubarb leaves, it is vital to act quickly and seek professional medical help. Do not wait for severe symptoms to appear. The national toll-free Poison Help hotline is a valuable resource.

• Call Poison Control: Contact your local poison control center or a national Poison Help hotline immediately.

• Seek Medical Attention: Be prepared to seek emergency medical treatment. Calling emergency services is appropriate for severe reactions.

• Provide Key Information: Have the person's age, weight, the amount and time of ingestion, and the plant name ready for the medical provider.

• Rinse and Dilute: If instructed, rinse the mouth thoroughly with water. If the person is conscious and not vomiting, a healthcare professional may advise giving them water or milk to dilute the concentration.

Comparison Table: Rhubarb Stalks vs. Leaves

Feature	Rhubarb Stalks	Rhubarb Leaves
Edibility	Edible	Toxic; Do not eat
Oxalic Acid Content	Low	High
Common Use	Used in pies, jams, and desserts	Not for consumption
Harvesting	Cut and use for cooking	Cut off and discard
Associated Risks	Low risk with proper preparation	Poisoning, kidney damage, severe complications
Taste	Tart and tangy	Astringent; not palatable

Conclusion

Understanding what are the symptoms of rhubarb poisoning is a crucial aspect of responsible gardening and nutrition. The toxic leaves, with their high concentration of oxalic acid, pose a significant risk, ranging from mild oral and gastrointestinal discomfort to life-threatening kidney failure and seizures in severe cases. The key to safety lies in simple, preventative measures: always discard the leaves, handle the plant with care, and seek immediate medical help if accidental ingestion occurs. By heeding these warnings, home cooks and gardeners can continue to safely enjoy the delicious, edible stalks of the rhubarb plant. The potential dangers serve as an important reminder to be mindful of all parts of the foods we consume.

For more information on handling poisonous plants, consult the Mount Sinai Health Library.

Frequently Asked Questions

What is the poisonous part of the rhubarb plant?

The large, heart-shaped leaves of the rhubarb plant are the poisonous part. They contain high concentrations of oxalic acid, which is toxic to humans and animals.

Are rhubarb stalks safe to eat?

Yes, the stalks of the rhubarb plant are safe and delicious to eat. They contain much lower levels of oxalic acid compared to the leaves and are the part used for cooking and baking.

What should I do if my pet eats rhubarb leaves?

If you suspect your pet has eaten rhubarb leaves, contact a veterinarian or a pet poison helpline immediately. Pets are more vulnerable to poisoning due to their smaller size.

How long do the symptoms of rhubarb poisoning last?

For mild cases, symptoms like stomach upset or vomiting may resolve within a few hours. In more severe poisonings, symptoms can last for 1 to 3 days and may require hospitalization.

Can cooking rhubarb leaves make them safe to eat?

No, cooking does not neutralize the toxic oxalic acid in rhubarb leaves. They should never be consumed, whether raw or cooked.

Is it safe to compost rhubarb leaves?

Yes, it is safe to compost rhubarb leaves. The oxalic acid breaks down quickly during the decomposition process. However, keep the compost pile away from pets and children.

What are the first signs of serious rhubarb poisoning?

Early signs of serious poisoning can include severe abdominal pain, difficulty breathing due to throat swelling, muscle tremors, or signs of kidney damage, such as red-colored urine.