Is Milkweed Toxic to Cats and Dogs?
Milkweed, a plant belonging to the Asclepias species, is toxic to dogs, cats, and horses. The American Society for the Prevention of Cruelty to Animals (ASPCA) confirms that these plants contain harmful substances. All parts of the milkweed plant are considered dangerous if a pet eats them.
The toxicity of milkweed varies between its different species. Some types contain cardiotoxins, which are compounds that affect the heart. Other species have neurotoxins, which impact the nervous system. Because of these potent compounds, ingestion can lead to serious health issues for an animal.
Milkweed: what the ASPCA database lists
| ASPCA entry | Milkweed |
|---|---|
| Other common names | None listed |
| Scientific name | Asclepias species |
| Family | Asclepiadaceae |
| Toxic to | Toxic to Dogs, Toxic to Cats, Toxic to Horses |
| Non-toxic to | None listed |
| Toxic principles | Some species contain cardiotoxins (steroidal glycosidic cardenolides) and other species contain neurotoxins. |
| Clinical signs listed | Vomiting, profound depression, weakness, anorexia, and diarrhea are common; may be followed by seizures, difficulty breathing, rapid, weak pulse, dilated pupils, kidney or liver failure, coma, respiratory paralysis and death |
What the ASPCA says about milkweed
According to the ASPCA, milkweed is toxic to dogs, cats, and horses. The danger comes from complex chemical compounds within the plant. Some milkweed species contain cardiotoxins, specifically steroidal glycosidic cardenolides, which interfere with cardiac function. Other species of the plant contain neurotoxins that affect the neurological system.
If a pet ingests milkweed, a range of clinical signs can appear. Initial symptoms often involve the digestive system and general well-being, including:
- Vomiting
- Profound depression
- Weakness
- Anorexia (loss of appetite)
- Diarrhea
The ASPCA warns that these signs can escalate to more severe, life-threatening conditions. These may include seizures, difficulty breathing, a rapid but weak pulse, and dilated pupils. In the most serious cases, poisoning can lead to kidney or liver failure, coma, respiratory paralysis, and death.
What this means for a home with pets
The presence of milkweed in a home, yard, or garden creates a significant risk for pets. All parts of the plant are toxic, so a curious dog or cat that chews on a leaf, stem, or flower can ingest a harmful amount of its toxins. Because the plant contains such potent compounds, even a small amount could be harmful.
The progression from initial signs like vomiting and weakness to severe neurological or cardiac problems can be swift. For this reason, any suspected ingestion of milkweed should be treated as a medical emergency. Prompt action and immediate veterinary care are critical.
Keeping pets and this plant apart
The most effective way to prevent milkweed poisoning is to ensure pets cannot access the plant. If you have a garden, consider fencing it off or choosing not to plant milkweed in areas where your pets play. When walking your dog, be mindful of wild plants in parks, fields, or along trails. Close supervision is key to preventing a curious pet from nibbling on unknown vegetation.
For indoor pets, especially cats, carefully check any bouquets or houseplants brought into the home. If you cannot confidently identify a plant as safe for pets, assume that it is not and place it well out of reach. While milkweed is not a common ingredient in pet foods, it is always a good habit to read ingredient labels on any new treats or supplements.
When to call your vet
If your pet chewed or ate part of this plant, call your veterinarian or an animal poison control line. Note which plant and which part, how much may be gone and when, and take a photo or a piece of the plant with you.
If you suspect your cat or dog has eaten any part of a milkweed plant, contact a veterinarian or the ASPCA Animal Poison Control Center immediately. Note what part of the plant was eaten, how much, and when the ingestion occurred. Do not wait for symptoms to appear before seeking professional help.
Emergency signs: go now
- Collapse, fainting or severe weakness
- Seizures, tremors or trouble standing
- Trouble breathing or blue, gray or very pale gums
- Repeated vomiting or retching, or a swollen, painful belly
- Any known contact with a substance listed as toxic, even before signs appear
Book an appointment soon
- Vomiting or diarrhea that lasts or keeps coming back
- Not eating or drinking, or drinking much more than usual
- Drooling, pawing at the mouth or a swollen face
- Lethargy, hiding or acting unlike themselves
ASPCA Animal Poison Control Center: (888) 426-4435 (a consultation fee may apply). Your own vet or nearest emergency clinic is always a good first call.
Sources
Last checked October 21, 2026. Listings and guidance can change; your veterinarian knows your pet’s health history.