Are Begonias Poisonous? – Toxicity Guide for Pets and People

Begonias are toxic to dogs, cats, and horses, and can cause GI irritation in people. The underground parts of the plant, the tubers and roots, contain the highest concentration of toxins. While most pet exposures result in relatively mild symptoms, the underground portions can cause more serious effects and should be treated with greater urgency.

What Part of Begonia Is Toxic?

Begonias (Begonia spp.) contain soluble calcium oxalates throughout the plant. The toxic compounds are concentrated most heavily in the underground parts, meaning the tubers and rhizomes that are often disturbed when repotting or when a dog digs up a garden plant. The leaves, stems, and flowers also contain oxalates but at lower levels.

Begonia is a large genus with over 1,000 species and 10,000 hybrids, covering everything from wax begonias sold at garden centers to large-leafed rex begonias popular as houseplants. Toxicity applies across the genus.

Symptoms of Begonia Poisoning

Dogs and cats: The most common signs are vomiting and drooling shortly after ingestion. Oral irritation from the oxalate crystals causes discomfort in the mouth and throat. In grazing animals such as horses, more serious effects including kidney failure have been documented with larger or repeated ingestion.

Humans and children: The oxalate crystals in begonias cause burning and irritation of the mouth, lips, and throat if chewed or swallowed. Nausea, vomiting, and abdominal discomfort can follow. Swallowing plant material may cause a sensation of swelling or difficulty swallowing due to irritation of the mucous membranes. Prolonged or repeated consumption of oxalate-containing plant material can contribute to kidney and urinary tract problems, though this is unlikely from a single accidental exposure.

Skin contact with the sap may cause irritation in sensitive individuals.

What to Do If Begonia Is Ingested

1. Remove any remaining plant material from the mouth and rinse with water.
2. Check whether the pet or child chewed on leaves and stems, or got into the tubers or root area, as the underground parts are more toxic.
3. Do not induce vomiting unless a medical professional directs you to.
4. Call your vet promptly if a pet has eaten any part of a begonia, especially the tubers.
5. Call poison control at 1-800-222-1222 (US) if a person has ingested begonia.
6. Watch for continued vomiting, difficulty swallowing, or signs of serious distress, which warrant immediate veterinary or medical attention.

Safe Handling and Placement

Begonias are popular houseplants and garden staples, so complete avoidance is often impractical. Risk management focuses on limiting access to the underground parts.

Practical steps:

• Keep potted begonias on shelves or surfaces out of reach of dogs and cats, particularly cats that like to chew foliage.
• When repotting, do not leave exposed tubers or roots accessible on the floor or low surfaces.
• In garden beds, monitor for dogs that dig, as unearthing a begonia tuber and chewing it is a more serious exposure than nibbling a leaf.
• Wear gloves when handling begonia tubers if you have sensitive skin.
• Wash hands after gardening with begonias.

If your household has a known plant-chewer, consider swapping begonias for non-toxic alternatives such as African daisy or spider plant.

Frequently Asked Questions

Are wax begonias as toxic as other begonias? All begonias contain soluble calcium oxalates and are classified as toxic by the ASPCA. Wax begonias have less toxin in the above-ground parts compared to the tubers, but they are still not safe for pets to eat.

My cat chewed a begonia leaf. Is this an emergency? Call your vet for guidance. Leaf ingestion typically causes drooling and vomiting rather than severe illness, but a vet can confirm whether monitoring at home is appropriate.

Are the flowers more or less toxic than the leaves? The underground tubers are the most toxic part. Above-ground parts including flowers and leaves are less dangerous but still not safe to eat.

Can begonias cause kidney failure in dogs? Kidney failure from begonias has been documented primarily in grazing animals ingesting large amounts. It is less commonly reported in dogs and cats from typical household exposures, but the risk is a reason to take ingestion seriously and consult a vet.

Are there begonia varieties that are safe for pets? No. The ASPCA lists begonias as toxic across the genus. There is no confirmed pet-safe begonia variety.