Dreamcatcher Alpacas
Plant safety · Caution

Can Alpacas Eat Yellow Star-thistle?

Yellow Star-thistle (Centaurea solstitialis) — a weed. Here is what alpaca owners need to know.

Updated 2026-10-02By the Dreamcatcher Alpacas editorial team
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Use caution — it depends on the amount and the situation.

Occasional nibbles are usually tolerated, but problems occur with large amounts, certain plant stages or vulnerable animals.

Yellow Star-thistle (Centaurea solstitialis)
Yellow Star-thistle (Centaurea solstitialis). Photo: Peggy Greb, Public domain via Wikimedia Commons.
Status
Caution
Scientific name
Centaurea solstitialis
Family
Asteraceae
Plant type
Weed
Toxic parts
Whole plant over weeks
Toxic compound
Repin (sesquiterpene lactone)
Region
Western U.S.

Why it matters

The neurological disease is documented in horses; camelid susceptibility is unknown. Spines are a definite fleece and mouth problem.

Signs of yellow star-thistle poisoning in alpacas

  • Difficulty chewing and grasping food ('chewing disease' in horses)
  • Spines injure mouths and contaminate fleece

If your alpaca ate a lot of yellow star-thistle

  1. Remove access and estimate how much was eaten.
  2. Watch for the signs listed above over the next 24–72 hours.
  3. Call your vet if any signs appear or if a pregnant, young or sick animal ate a large amount.
  4. Reduce the plant in your pasture and keep good forage available so alpacas aren't driven to eat it.

About the plant

Centaurea solstitialis, the yellow star-thistle, is a species of thorny plant in the genus Centaurea, which is part of the family Asteraceae. A winter annual, it is native to the Mediterranean Basin region and invasive in many other places. It is also known as golden starthistle, yellow cockspur and St. Barnaby's thistle.From Wikipedia — “Centaurea solstitialis”, licensed under CC BY-SA 4.0.

Where it grows

Main range of concern: Western U.S.. GBIF, the Global Biodiversity Information Facility, holds 31,971 recorded observations of Centaurea solstitialis L. worldwide, including 11,261 in the United States. It belongs to the Asteraceae family, together with Cocklebur, Common Groundsel, Rayless Goldenrod, Tansy Ragwort, White Snakeroot. See the occurrence map on GBIF.

Frequently asked questions

Is yellow star-thistle poisonous to alpacas?
It can be. Use caution — it depends on the amount and the situation. The neurological disease is documented in horses; camelid susceptibility is unknown. Spines are a definite fleece and mouth problem.
What part of yellow star-thistle is toxic to alpacas?
Whole plant over weeks.
What are the symptoms of yellow star-thistle poisoning?
Difficulty chewing and grasping food ('chewing disease' in horses) and spines injure mouths and contaminate fleece.
Is dried yellow star-thistle safe?
Drying does not reliably make poisonous plants safe. Treat dried leaves and contaminated hay with the same caution.

Keeping pastures safe

  • Walk every paddock and fence line each season and remove toxic plants, including roots.
  • Never throw garden, hedge or lawn clippings over the fence.
  • Check pastures after storms for fallen branches (cherry, red maple).
  • Buy hay from known sources and inspect it for weeds.
  • Keep pastures well managed — hungry alpacas eat plants they would normally avoid.

Browse the full toxic plant checker, the printable list of poisonous plants and the list of safe plants.

This page is educational and does not replace advice from a veterinarian who has examined your animals. Camelid medicine uses many drugs “extra-label”, so dosing must come from your vet. In an emergency, call your vet first. Read our disclaimer · How we write and review content.

Data: plant status compiled from veterinary toxicology references (see sources); taxonomy and occurrences from GBIF; identifiers from Wikidata Q2068262.