Is it toxic to dogs?
Milkweed
Asclepias spp. · Apocynaceae
Also called Butterfly weed, Common milkweed, Swamp milkweed, Tropical milkweed
Toxic to dogs
Severity: Severe
Yes. The ASPCA lists milkweed as toxic to dogs, and it is a plant to take seriously. Some species contain compounds that affect the heart, and serious cases can involve seizures, organ failure and death.
- Toxic parts
- All parts (Pet Poison Helpline and Merck)
- Toxic compounds
- Cardiotoxic steroidal glycosidic cardenolides in some species; neurotoxins in others
- Where you’ll find it
- Garden
- When signs start
- Merck says signs from this group of heart-affecting plants are expected within about 2 hours and can last several days.
Signs of poisoning
- Vomiting
- Profound depression
- Weakness
- Loss of appetite
- Diarrhea
- Abnormal heart rhythm or rate
- Dilated pupils
- Tremors or seizures
- Difficulty breathing
- Kidney or liver failure (severe cases)
Why it’s harmful to dogs
Milkweed is the plant gardeners add on purpose for monarch butterflies, and it also grows wild along roadsides, meadows and field edges. Common milkweed, swamp milkweed, butterfly weed and tropical milkweed are all Asclepias species.
The ASPCA says some Asclepias species contain cardiotoxins (steroidal cardenolides) and others contain neurotoxins. Pet Poison Helpline explains that cardiac glycosides disturb the electrolyte balance in heart muscle and can cause abnormal heart rhythms and dangerously high potassium. The Merck Veterinary Manual says all parts of milkweed are considered toxic and places it among the cardiac glycoside plants, which it describes as some of the most toxic plants there are, with little room for error.
The ASPCA's list of possible signs runs from vomiting and weakness to seizures, organ failure, coma and death. Dogs meet milkweed in butterfly beds, naturalized patches and cut arrangements, so it deserves a spot on your risk list.
If your dog ate milkweed
Treat any real chewing on milkweed as a reason to call, even if your dog seems fine. Call your vet, an emergency clinic, or ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 (US; fees may apply) right away and tell them it was milkweed and, if you know, which kind.
Heading to the clinic is the safest move if your dog is weak, vomiting, has tremors or seizures, or has an odd heartbeat or trouble breathing. Outside the US, contact your local emergency vet. Don't try to make your dog vomit at home. Take a leaf or photo of the plant, note the time, and bring any bouquet or clippings with you.
Keeping your dog safe
Plant milkweed in a fenced pollinator bed rather than in open lawn, and pull wild seedlings that pop up in dog areas. Keep cut stems out of vases that dogs can reach, and clear clippings quickly.
If your dog roams or digs, think twice about adding milkweed at all. For a pollinator-friendly garden with less risk, choose plants the ASPCA lists as non-toxic, such as sunflowers and petunias. Practice a strong "leave it" on field walks, where wild milkweed often grows.
Dog-safe alternatives
Frequently asked questions
Which part of milkweed is toxic?
Merck considers every part of the plant toxic, and Pet Poison Helpline agrees. That includes leaves, stems, flowers and the milky sap.
Is a small bite of milkweed an emergency?
It can be hard to know how much is too much, because toxicity varies by species and plant part. Call your vet or a poison hotline right away rather than waiting to see.
Are all milkweeds equally dangerous?
No. The ASPCA says some species contain heart toxins and others contain neurotoxins. Because species are hard to tell apart, treat every milkweed as dangerous.
Written from veterinary sources by the Pawsplained editorial team. Not yet reviewed by a veterinarian; this is general information, not a diagnosis or treatment plan. Updated Oct 30, 2026. Editorial policy