Ursodiol (ursodeoxycholic acid) is a naturally-occuring bile acid sometimes used to treat dogs with liver disease and to dissolve or prevent the formation of cholesterol-containing gallstones. It has several effects including the ability to suppress bile flow, reduce the secretion of cholesterol, decrease the amount of cholesterol absorbed by the intestines and reduce the liver-toxic effects of bile salts. It is also known by the trade name Actigall.

It seems to be well tolerated by dogs, producing few side effects, though it can inhibit the metabolism of bile acid.

Ursodiol Dosage For Dogs

Note: Do not give ursodiol to your dog without permission from your vet, and do not use substitutes such as TUDCA (ursodeoxycholic acid bound to taurine).

The usual dosage of ursodiol when treating dogs is 2.5 – 3.4 mg/lb given with food every 12 hours for chronic hepatitis, cystic fibrosis and primary biliary cirrhosis. A dosage toward the top of the range is often used.
Graph showing the ursodeoxycholic acid dosage for dogs

Dog’s Weight In Pounds: Dosage In Mg:

Some vets prefer to use a different dosage or administer the medicine once daily. Follow the exact dosing recommendations of your vet.

Example: 100 mg twice daily could be used for a 30 lb dog.


Is It Safe?

Ursodiol is likely safe for healthy dogs, but practice caution in those with conditions associated with gallstones including:

  • Bile duct obstruction
  • Biliary fistula
  • Cholangitis
  • Cholecystitis
  • Pancreatitis

The drug is metabolized into lithocolic acid, a liver-toxic substance. This could be problematic in dogs who are unable to sulfate lithocolic acid.

Pregnancy/Nursing: May be unsuitable for pregnant or nursing dogs. Seek advice from your vet.

Safety Guidelines

These guidelines will help you to use ursodiol safely:

  • Do not use without veterinary permission
  • Tell the vet about any medical conditions your dog is affected by, particularly complications related to gallstones
  • Tell the vet about any supplements or medicines your dog is taking
  • Avoid use with aluminum antacids (e.g. Gaviscon) or estrogens unless directed to do so by your vet

AST/ALT ratio tests should be performed routinely. Based on use of the drug in humans, this test should be carried out when first starting therapy, after one and three months, and then every six months. Monitor liver blood values for signs of improvement, and use ultrasound to monitor signs of improvement in gallstones.

Do not substitute with TUDCA, as TUDCA may have slightly different effects.

What Is It Used For?

The following conditions may benefit from primary treatment or adjunctive therapy with ursodiol:

  • Cholesterol-containing gallstones
  • Chronic hepatitis
  • Cystic fibrosis
  • Primary biliary cirrhosis

It may also be useful for protecting the liver from various -cholate substances which are toxic to the liver, such as deoxycholate.

It is not effective for dissolving calcified gallstones or pigment gallstones.

Side Effects

The drug is usually tolerated well by dogs, but could potentially cause the following effects:

  • Diarrhea
  • Vomiting
  • Itching
  • Jaundice
  • Impaired liver function
  • Allergic reactions

Notify the vet if your dog experiences any side effects. Regular blood testing will pick up on alterations in liver function.


Overdoses may cause diarrhea, but won’t often require treatment. Despite this, if you suspect an overdose get in contact with the vet or a pet poison specialist right away. You can reach the ASPCA poison control hotline on (888) 426-4435. Treatment of overdose may include the use of aluminum antacids to reduce absorption, emptying of the stomach and the use of activated charcoal.


Dr. T. Tams
Plumb’s Veterinary Drug Handbook (sixth edition)