If an animal has eaten this plant, the ASPCA Animal Poison Control Center is (888) 426-4435, as printed on the record this page reproduces. A consultation fee may apply.
This page quotes a published document. Everything below in quotation marks is copied word for word from ASPCA Animal Poison Control Center: Rayless Goldenrod, published by ASPCA APCC and retrieved on 2026-09-16. The quotations are excerpts; the document itself is linked and is the authority. Nothing has been reworded.
According to the ASPCA Animal Poison Control Center record, Rayless Goldenrod (Haplopappus heterophyllus, family Asteraceae) is toxic to horses. Toxic principles: Trematol. Clinical signs listed: Plant is toxic year round, although poisonings typically occur in summer and late fall. Horses eating one to ten percent of their body weight in the plant can develop lethal clinical effects. Onset of signs generally occurs after two days to three weeks, and includes incoordination, muscle weakness and tremors, elevated heart rate, cardiac arrhythmias, fluid accumulation and swelling of the nervous system, profuse sweating, inability to swallow. The record was retrieved on 2026-09-16 and is linked below.
The record
- Scientific name
- Haplopappus heterophyllus
- Family
- Asteraceae
- Toxicity
- Toxic to Horses
- Toxic principles
- Trematol
- Clinical signs
- Plant is toxic year round, although poisonings typically occur in summer and late fall. Horses eating one to ten percent of their body weight in the plant can develop lethal clinical effects. Onset of signs generally occurs after two days to three weeks, and includes incoordination, muscle weakness and tremors, elevated heart rate, cardiac arrhythmias, fluid accumulation and swelling of the nervous system, profuse sweating, inability to swallow.
Where this comes from
This is the ASPCA Animal Poison Control Center record for Rayless Goldenrod, at https://www.aspca.org/pet-care/aspca-poison-control/toxic-and-non-toxic-plants/rayless-goldenrod, retrieved on 2026-09-16. The fields above are the record’s own, shown without change. The ASPCA keeps the record current; the page here is a copy from that date.
This page is information, not a prescription. The right dose for an animal depends on its weight, its age, what else it is taking and what is wrong with it. Those are judgements only the veterinarian who has examined your animal can make. Ring your practice before giving anything.
Sources
- ASPCA Animal Poison Control Center: Rayless GoldenrodASPCA APCC · retrieved 2026-09-16
“Plant is toxic year round, although poisonings typically occur in summer and late fall. Horses eating one to ten percent of their body weight in the plant can develop lethal clinical effects. Onset of signs generally occurs after two days to three weeks, and includes incoordination, muscle weakness and tremors, elevated heart rate, cardiac arrhythmias, fluid accumulation and swelling of the nervous system, profuse sweating, inability to swallow.” (Clinical Signs)
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