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Diethylstilbestrol (DES) for Dogs: Incontinence & Prostate Treatment

Published on September 10, 2024
Updated on November 5, 2025
Reviewed by Petco's Veterinarian Team
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Synthetic estrogen hormone historically used to treat urinary incontinence in spayed female dogs and benign prostatic hypertrophy (enlarged prostate) in male dogs.

The use of diethylstilbestrol (DES) is controversial and no longer common. Clients should use personal protective equipment (wear gloves and/or wash hands after touching) to minimize risk of exposure. Pregnant women should avoid handling DES.

Summary

Used For:

Historical use for urinary incontinence in spayed female dogs

Brands:

None available in the US

Species:

Dogs

Other names:

DES, Diethylstilbestrolum, Stilbestrol, Stilboestrol, NSC-3070

Drug type:

Endocrine

Prescription required:

Yes

Pregnancy and lactation:

Not safe for use in pregnant or lactating animals.

Side effects:

Bone marrow toxicity, GI effects, mammary cancers, uterine disease, feminization in males

General description

Diethylstilbestrol is a synthetic estrogen hormone that was historically used in the treatment of urinary incontinence in female dogs and benign prostatic hypertrophy (prostate enlargement) in male dogs. The use of diethylstilbestrol for the prevention of pregnancy is not recommended due to potential serious side effects.

Uses

The use of diethylstilbestrol in general has become controversial with the FDA approval of the drug estriol (Incurin).

How it works

Diethylstilbestrol binds to the estrogen receptors in the tissues of the body, including the reproductive tract and urinary tract (bladder).

Dosage

Dogs: 0.1-1 milligram per dog by mouth for 3-5 days, then taper to every other day, then taper to lowest effective dose (typically 1-3 times per week).

Forms

Stilbestrol tablets for oral use in 0.5 and 1 milligram sizes. (Canada)

Storage information & handling

Tablets should be stored at room temperature in a tight container. Keep out of the reach of children and measures should be taken to prevent exposure in pregnant women due to risks to the fetus.

What results can I expect?

Reduced urine leaking or dribbling incontinent spayed female animals, reduces prostate size in male dogs.

Missed Dosage

If a dose is missed, continue with the next dosage at the scheduled time.

Overdose / acute toxicity

No information available regarding acute toxicity or overdose in veterinary medicine. Contact your veterinarian or poison control if you believe your pet received an overdose of diethylstilbestrol.

Side effects

May include:

  • Bone marrow toxicity (decreased production of blood cells)
  • Gastrointestinal upset
  • Pyometra (uterine infection)
  • Cystic endometrial (uterine) hyperplasia
  • Mammary (breast) cancers
  • Feminization of male animals
  • Heart, liver and pancreatic lesions in cats

Contraindications

Avoid use in:

  • Pets with known sensitivity to estrogens
  • Females with estrogen-sensitive cancers

Drug interactions

*Antifungal medications can increase estrogen levels.

*Cimetidine, erythromycin and clarithromycin may decrease the metabolism of estrogen.

*Phenobarbital and phenytoin may decrease estrogen concentrations.

*Rifampin may decrease estrogen levels.

*The activity of anticoagulants such as warfarin may be decreased by estrogen.

*Estrogen may enhance the effects of corticosteroids.

*Estrogens may diminish the therapeutic effect of levothyroxine, and an increase in levothyroxine dose may be needed.

*May decrease efficacy of tricyclic antidepressants (eg, amitriptyline, clomipramine).

Precaution

Use with caution in patients with liver disease, pre-existing anemia or low blood counts, and young patients. High doses can cause ovarian cancer in dogs.

Clients should use personal protective equipment (wear gloves and/or wash hands after touching) to minimize risk of exposure. Pregnant women should avoid handling DES.

Laboratory considerations

CBC due to potential blood dyscrasias. Monitor thyroid levels closely in patients on thyroid supplementation.

Sources

Plumb’s Veterinary Drug Handbook

Manufacturer information: Ormond Veterinary Supply (Canada)

Disclaimer
The information contained on this page is for educational purposes only. This medication should only be given under the advice of a veterinarian who has examined your pet under the laws applicable to your state of residence.

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