Yellow Wood Sorrel Poisoning in Horses

Yellow Wood Sorrel Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
Yellow Wood Sorrel Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is Yellow Wood Sorrel Poisoning?

The yellow wood sorrel looks very similar to clover or shamrock plants, with three heart shaped leaves that grow close to the ground (usually under 12 inches high) and small yellow flowers. The soluble oxalates in the plant will quickly be absorbed and bind with magnesium and calcium in your horse’s body. This limits the amount of these important elements in the system and causes a severe metabolic imbalance. Due to the increased amount of calcium in the kidneys, kidney stones and blockages may occur and cause kidney damage, which may be lethal.

Yellow wood sorrel poisoning in horses is a dangerous condition caused by eating any plant of the sorrel (oxalis) variety. These plants contain soluble calcium oxalates (oxalic acid) which can produce a serious reaction of colic and inability of the blood to clot. Some things your horse may suffer from with this condition include gastric distress, respiratory problems, burning of the mouth and throat, impaired blood clotting, kidney failure, coma, and death. Since the oxalates are soluble, the toxin is easily absorbed into the bloodstream, which makes it a fast-acting and serious problem, especially with the renal system.

Symptoms of Yellow Wood Sorrel Poisoning in Horses

The symptoms of yellow wood sorrel poisoning include:

  • Appetite loss
  • Excessive drooling
  • Burning mouth and throat
  • Diarrhea
  • Abdominal pain
  • Weakness
  • Irregular heart rate
  • Shivering or shaking
  • Respiratory distress
  • Dark brown or red urine (blood in the urine)
  • Hemorrhaging
  • Kidney failure (extreme fatigue, increased thirst and urination)
  • Convulsions
  • Coma
  • Death


The botanical name of yellow wood sorrel is Oxalis stricta from the Oxalidaceae family. Some additional common names are:

  • Common yellow oxalis
  • Lemon clover
  • Oxalis stricta var. villicaulis
  • Oxalis stricta var. rufa
  • Oxalis stricta var. piletocarpa
  • Oxalis stricta var. decumbens
  • Pickle plan
  • Shamrock plant
  • Sorrel
  • Sourgrass
  • Upright yellow-sorrel


Causes of Yellow Wood Sorrel Poisoning in Horses

The poisonous substances in the yellow wood sorrel are soluble calcium oxalates (oxalic acid). Eating any part of this plant can cause colic and kidney failure if enough is consumed. Some common reasons your horse may be consuming this plant are:

  • Lack of safe forage
  • Plants accidentally mixed with hay
  • Boredom


Diagnosis of Yellow Wood Sorrel Poisoning in Horses

Call the veterinary (or emergency clinic) immediately to find out if there is anything you can do at home before trying to move your horse. It may be beneficial to find a veterinarian that will make house calls due to the danger of moving a horse in serious condition. Also, the veterinarian may have some treatments you can do at home to prevent a visit if possible. This is usually only the case with a minimal consumption. If your horse consumed a large amount, you should not wait to call the veterinarian, just go straight to the veterinarian or emergency clinic. Try to bring a sample or photograph of the plant to help the veterinarian with the diagnosis. You should also be prepared to answer detailed questions about your horse’s medical history, recent illnesses and injuries, immunization records, and any drugs your horse has been given in the past few days.

Routine blood tests may reveal decreases of calcium and magnesium, increased blood urea nitrogen (BUN), anemia (low iron), and azotemia (excess creatinine). In addition, decreased potassium, chloride, and sodium may be revealed because the tubules may be blocked or inflamed. A urine sample will probably indicate blood, glucose, and protein in the urine and a low specific gravity. Radiographs (x-rays) will be done to check for kidney damage, stones, and other underlying problems.



Treatment of Yellow Wood Sorrel Poisoning in Horses

The treatment usually includes evacuation, medications, fluid and oxygen supplements, and a special diet.


Evacuating the toxins from the body is the first thing your veterinarian should do is to give your horse activated charcoal by mouth to bind the unabsorbed toxins. Afterward, the veterinarian will perform a lavage of the gastrointestinal tract by inserting a tube into the nose or mouth and running warm water through the stomach and intestines to rinse away any residual toxicities. This procedure is done while your horse is sedated.


Your veterinarian may give your horse Lasix to reduce swelling, omega 3 fatty acids for the kidney function, antibiotic in case of infection, and phenylbutazone for pain.

Fluid and Oxygen

Fluids and electrolytes by intravenous (IV) line will help circulation and flush the kidneys while preventing dehydration. Oxygen is usually provided right away if your horse is in respiratory distress.

Special Diet

The veterinarian may suggest a diet of low calcium and high in protein.



Worried about the cost of Yellow Wood Sorrel Poisoning treatment?

Pet Insurance covers the cost of many common pet health conditions. Prepare for the unexpected by getting a quote from top pet insurance providers.

Recovery of Yellow Wood Sorrel Poisoning in Horses

If you were able to obtain veterinary treatment right away, your horse has a good chance of survival. You will have to continue to monitor your horse’s urine output for several months to prevent a relapse.



Yellow Wood Sorrel Poisoning Questions and Advice from Veterinary Professionals

Need pet insurance?
Need pet insurance?

Learn more in the Wag! app

Five starsFive starsFive starsFive starsFive stars

43k+ reviews


© 2022 Wag Labs, Inc. All rights reserved.