Major Uses

Diethylstilbestrol is a hormonal agent that is primarily used as a synthetic estrogen to treat estrogen responsive incontinence and other estrogen indications in spayed female dogs. It can also be used to treat benign prostatic hypertrophy in male dogs. It has been used to prevent pregnancy after mismating in female dogs and cats, but is generally no longer used for this purpose because of the potential for serious side effects.

Common Precautions

Diethylstilbestrol is not for use in food animals due to FDA restrictions. It can also have effects on bone marrow and therefore should be used with caution in patients suffering from preexisting anemias or leukopenias.

Diethylstilbestrol is considered toxic to bone marrow in dogs and cats and can cause blood dyscrasias, though this is more common in older animals and at high doses. Diethylstilbestrol can also cause thrombocytosis and leukocytosis, normochromic, normocytic anemia, bone marrow depression, aplastic anemia, mammary neoplasias, neutropenia. And pancreatic, hepatic, and cardiac lesions. Other symptoms can include cystic endometrial hyperplasia, pyometra, feminization in male animals, estrus, malignant ovarian adenocarcinoma, and death.

Diethylstilbestrol should not be used in animals with a known allergy or hypersensitivity to the drug. A veterinarian should be contacted immediately if an overdose is suspected, the symptoms of which include nausea, vomiting, and withdrawal bleeding.


Diethylstilbestrol should be kept at room temperature in a childproof, light resistant container. It should be stored where it cannot be reached by children and pets.


For estrus induction in dogs, a typical dose of diethylstilbestrol is 5 mg a day for 7 days, upping the dose to 10 mg a day for another 7 days if no change is noted after the first 7 doses. For treating prostatic hyperplasias in dogs, a typical dose is .2-1 mg total for 5 days. For treating estrogen-responsive incontinence in cats, a typical dose is .1-1 mg once daily for 5 days, followed by 1 mg once a week. Should a dose be forgotten, it should be given as soon as possible. Two doses should never be administered at the same time, so if it is almost time for the next scheduled dose, the missed dose should be skipped.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.