The Catalpa tree, commonly known as the cigar tree or Indian bean tree, is a popular ornamental species recognized for its large leaves and long, bean-like seed pods. While the tree is frequently labeled as toxic, the risk level to humans and most animals is generally considered low for casual exposure. Caution is still warranted because the plant contains compounds that can cause illness, and certain parts are more hazardous than others.
Which Parts of the Catalpa Tree Pose a Risk?
The most acutely poisonous part of the Catalpa tree is the root system. The concentration of toxic compounds in the roots is significantly higher than in the above-ground tissues, making them the primary source of severe danger. However, commonly encountered parts like the leaves, flowers, bark, and the distinctive long seed pods also contain chemical defenses.
These above-ground parts contain iridoid glycosides, such as catalpol and catalposide. These compounds serve as the tree’s natural protection and give the tissues a bitter taste, which often prevents consumption of a large enough quantity to cause serious harm. The long seed pods, which resemble cigars, are the most frequently ingested part.
While consumption of small amounts of leaves or pods typically results only in mild discomfort, the potential for greater effects exists if a substantial quantity is ingested. Historical use of prepared bark and seeds in medicinal applications suggests they are not acutely life-threatening in small, processed doses.
Symptoms of Catalpa Ingestion in Humans and Animals
Ingestion of the above-ground parts of the Catalpa tree, such as the leaves or pods, commonly results in mild gastrointestinal (GI) distress in both humans and animals. Symptoms typically include vomiting, diarrhea, and stomach pain. These effects are attributed to the iridoid glycosides, which irritate the digestive tract.
In household pets, particularly dogs, ingestion often leads to lethargy and a reduced appetite in addition to the GI upset. While mild symptoms are the norm, ingestion of a very large quantity, or the highly toxic root material, has been associated with severe reactions in animals. These symptoms can include muscle tremors, seizures, and signs of cardiac or neurological issues.
If a child or pet is suspected of ingesting any part of the Catalpa tree, take immediate action. For human ingestion, contact Poison Control immediately to assess the risk based on the amount and part consumed. For pets, contact your veterinarian or the ASPCA Animal Poison Control Center. Never attempt to induce vomiting without guidance from a medical professional.
Addressing the Misinformation Surrounding Catalpa Toxicity
The persistent confusion regarding the Catalpa tree’s toxicity often stems from two primary factors: its historical use and its resemblance to other plants. For centuries, various parts of the Catalpa were utilized in traditional medicine, which contributes to the conflicting information found today. Decoctions made from the bark, seeds, and pods were historically used as a sedative, a treatment for asthma, and even as an antiseptic.
This medicinal history suggests that the plant was not seen as universally deadly, but rather as having powerful, dose-dependent properties. The second major source of confusion is the tree’s close visual similarity to the highly invasive Princess Tree, Paulownia tomentosa. Both trees share large, heart-shaped leaves, but the Princess Tree is distinct with its lavender or purple flowers and small, rounded seed capsules.
Because the appearance is so similar, a casual observer may mistake one for the other, leading to misattribution of toxicity reports. The Catalpa’s flowers are white, and its fruit is the characteristic long, brown, cigar-like pod. Due to the potential for misidentification and the known toxicity of the roots, caution remains prudent, validating the need for clear information about this common landscape tree.