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: Yellow Starthistle, 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, Yellow Starthistle (Centaurea solstitialis, family Compositae) is toxic to horses. Toxic principles: Unknown. Clinical signs listed: The plant is not usually eaten unless other forage is unavailable, or when incorporated into hay. Poisonings occur at ingestions of 50%- 200% of the animal's body weight over a 60 to 90 day period of grazing. Clinical signs have been referred to as "chewing disease", where horses chew but are unable to obtain food or swallow. Signs seen include a grinning appearance, open mouth with protruding, lolling tongue, yawning, head tossing, central nervous system depression, lost interest in food, difficulty breathing due to inhalation of food, submerging the head in water in an attempt to drink. Death can occur due to lack of eating and drinking, leading to dehydration and malnutrition. The record was retrieved on 2026-09-16 and is linked below.
The record
- Scientific name
- Centaurea solstitialis
- Family
- Compositae
- Toxicity
- Toxic to Horses
- Toxic principles
- Unknown
- Clinical signs
- The plant is not usually eaten unless other forage is unavailable, or when incorporated into hay. Poisonings occur at ingestions of 50%- 200% of the animal's body weight over a 60 to 90 day period of grazing. Clinical signs have been referred to as "chewing disease", where horses chew but are unable to obtain food or swallow. Signs seen include a grinning appearance, open mouth with protruding, lolling tongue, yawning, head tossing, central nervous system depression, lost interest in food, difficulty breathing due to inhalation of food, submerging the head in water in an attempt to drink. Death can occur due to lack of eating and drinking, leading to dehydration and malnutrition.
Where this comes from
This is the ASPCA Animal Poison Control Center record for Yellow Starthistle, at https://www.aspca.org/pet-care/aspca-poison-control/toxic-and-non-toxic-plants/yellow-starthistle, 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: Yellow StarthistleASPCA APCC · retrieved 2026-09-16
“The plant is not usually eaten unless other forage is unavailable, or when incorporated into hay. Poisonings occur at ingestions of 50%- 200% of the animal's body weight over a 60 to 90 day period of grazing. Clinical signs have been referred to as "chewing disease", where horses chew but are unable to obtain food or swallow. Signs seen include a grinning appearance, open mouth with protruding, lolling tongue, yawning, head tossing, central nervous system depression, lost interest in food, difficulty breathing due to inhalation of food, submerging the head in water in an attempt to drink. Death can occur due to lack of eating and drinking, leading to dehydration and malnutrition.” (Clinical Signs)
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