Is Silk Vine Poisonous? – Toxicity to Humans, Dogs, and Cats

Yes. Silk vine (both Periploca graeca and Periploca sepium) is poisonous to humans, dogs, cats, and horses. The sap and fruit contain toxic compounds that can cause vomiting, diarrhea, and skin irritation. Fatal poisoning is not documented, and most exposures result in mild to moderate gastrointestinal upset. Still, treat it as a plant you do not want to eat or let your pets chew on.

What Is Silk Vine?

Silk vine refers to two species of twining climbers in the Apocynaceae (dogbane/milkweed) family:

• Periploca graeca - the species most commonly called silk vine. Native from southeastern Europe through western Asia. Grown ornamentally on walls, fences, and obelisks.
• Periploca sepium - called Chinese silk vine. Native to China and eastern Asia. Used in similar ornamental contexts.

The plant can reach 9 to 10 metres (29 to 33 feet) when grown on a support. Leaves are opposite, oval to ovate, waxy, and dark green. Flowers are star-shaped, roughly 2 to 3 cm across, and appear in summer. P. graeca produces purple-brown blooms; P. sepium tends toward yellow-green. Both have an unpleasant scent. The fruit consists of paired seed pods about 10 cm long. Each seed carries a silky white tuft, which gives the plant its common name and helps with wind dispersal.

Gardeners encounter silk vine most often as an ornamental climber on structures. It is hardy, vigorous, and low-maintenance once established.

Why Is Silk Vine Poisonous?

Both species produce a milky sap typical of the Apocynaceae family. This sap is released when stems are cut, broken, or damaged. It contains toxic compounds that irritate skin and, if ingested, cause gastrointestinal distress.

The Apocynaceae family includes oleander (Nerium oleander), which is notoriously toxic. Silk vine shares this family connection, which is why botanical sources flag it as poisonous. However, the toxicity of silk vine is considerably milder than oleander. Fatal cases are not documented in the literature for Periploca graeca or P. sepium. The specific toxins in silk vine are not well-characterized, but the plant is consistently listed as poisonous in RHS, PFAF, and NC State Extension databases.

The fruit is toxic if ingested. The seeds are enclosed within the fruit, so the same applies to them. The silky seed tufts themselves are not known to be toxic, but the seeds inside them are.

A note on historical use: PFAF and other sources record that silk vine was used historically as a cardiac tonic and diuretic in some folk medicine traditions. This is not current medical advice. The plant is not safe to self-medicate with, and historical use does not make it safe for casual consumption.

Toxicity to Humans

Skin contact: The milky sap can cause irritation, particularly in sensitive individuals. Wash the affected area with soap and water promptly. If sap gets in your eyes, rinse thoroughly with water and seek medical advice if irritation persists.

Ingestion: Eating the fruit or sap can cause nausea, vomiting, diarrhea, and abdominal discomfort. These symptoms are generally mild to moderate. If ingestion occurs, contact Poison Control at 1-800-222-1222 (US). Rinse the mouth with water. Do not induce vomiting unless directed by a medical professional.

Safe handling: Wear gloves when pruning or cutting back silk vine. Wash your hands thoroughly after handling any damaged stems or fruit.

Toxicity to Pets (Dogs, Cats, Horses)

Silk vine is poisonous to dogs, cats, and horses. The primary symptoms, based on botanical databases and veterinary plant toxicity references, are vomiting and diarrhea. These occur because the toxic compounds in the sap and fruit irritate the gastrointestinal tract.

The ASPCA Animal Poison Control Center and Pet Poison Helpline do not have specific entries for Periploca, but the plant is consistently listed as harmful in botanical references that cover animal toxicity.

If your dog or cat chews on any part of the plant, contact your veterinarian or the Pet Poison Helpline (855-764-7661). The ASPCA Poison Control Center is available at 888-426-4435. Watch for vomiting, diarrhea, drooling, and lethargy. Symptoms are typically gastrointestinal and self-limiting, but it is always best to get professional guidance rather than wait.

Horses are also susceptible. Keep horses away from silk vine, particularly if you are pruning or clearing growth where they have access.

What to Do If Ingestion Is Suspected

Skin contact: Rinse the area with water and wash with soap. If eyes are affected, flush with clean water for several minutes. Seek medical advice if irritation is significant.

Pet ingestion: Call your vet or Pet Poison Helpline immediately. Do not induce vomiting at home unless specifically directed. Bring a photo or sample of the plant if possible to help with identification.

Human ingestion: Call Poison Control (1-800-222-1222 in the US) or your local emergency number. Rinse the mouth with water. Do not induce vomiting unless a medical professional instructs you to.

Safe Handling and Garden Context

Silk vine is not a plant to fear, but it deserves respect. It is not safe to eat, and you should handle it with gloves when doing any cutting or pruning. Keep pets away from pruned material and do not let them chew on fallen stems or fruit.

The toxicity level is lower than other Apocynaceae such as oleander. You do not need to remove an established silk vine from your garden solely because of toxicity concerns, provided you handle it appropriately and supervise pets and children around it.

If you are looking for a non-toxic alternative climber with a similar growth habit, consider Clematis species (some are toxic to pets, so check specific varieties) or Boston ivy (Parthenocissus tricuspidata), which is generally considered non-toxic.

FAQ

Is silk vine the same as milkweed? No, but they are in the same family (Apocynaceae). Milkweed (Asclepias) and silk vine (Periploca) are cousins, not the same plant. Both produce milky sap and both are toxic to some degree.

Which species of silk vine is more toxic? Both Periploca graeca and P. sepium are listed as poisonous in botanical references. There is no evidence that one species is significantly more toxic than the other.

My dog ate a piece of silk vine. What should I watch for? Vomiting and diarrhea are the most common symptoms. Drooling and lethargy are also possible. Contact your vet or Pet Poison Helpline. Monitor your dog and seek care if symptoms are severe or persistent.

Can I touch silk vine with bare hands? Brief, casual contact (e.g., brushing against foliage) is unlikely to cause problems for most people. Repeated contact or contact with the sap can cause skin irritation. Wearing gloves when handling the plant is the safer choice.

Is the silk from the seed pods dangerous? The silky seed tufts are the wind-dispersal mechanism, not a toxic part. However, the seeds inside the pods are considered toxic. If you handle seed pods, wash your hands afterward.