What is diethyl stilbestrol (DES)?

Diethylstilbestrol (DES) is a synthetic nonsteroidal estrogen that was first synthesized in 1938. Human exposure to DES has allegedly occurred through diverse sources, such as dietary ingestion from supplemented cattle feed and medical treatment for certain conditions, including breast and prostate cancers.

From 1940 to 1970, DES was actually given to pregnant women in the belief that it would reduce the risk of pregnancy complications and losses. In 1971, DES was shown to cause a rare vaginal tumour in girls and young women who had been exposed to this drug in utero and the US FDA subsequently withdrew DES from use in pregnant women.

Dan Lednicer offered us a guest editorial some time ago that mentioned the ill-fated drug diethyl stilbestrol (DES) and the toxicity of this and other compounds. Here’s the 3D chemical structure of DES for recent visitors to Sciencebase who were looking for it!

Diethylstilbestrol is an orally active non-steroidal estrogen first made in 1938 and originally approved for use in gonorrheal vaginitis, atrophic vaginitis, for menopausal symptoms, and in postpartum lactation suppression to prevent breast engorgement.

However, in 1971 it was found to be a teratogen – causing birth defects – when given to pregnant women and later a carcinogen. It is currently used only in veterinary practice at very low (hypocarcinogenic) doses for treating female canine incontinence.

Author: David Bradley

Freelance science journalist, author of Deceived Wisdom. Sharp-shooting photographer and wannabe rock god.

8 thoughts on “What is diethyl stilbestrol (DES)?”

  1. Hi Kathy,

    Natli is doing fine, touch wood…she has been on DES and does not wet herself anymore, appears more confident and not nervous and scared anymore. My vet had advised me not to discontinue DES for her as constant wetting can lead to infection of the urinary track – which is a serious problem to tackle and quite painful for the dog. According to my Vet, the only known side effect of DES is cancer of the utres in some cases – but as Natli is spayed, this is not a concern.

    Natli has become very fat, has spondylitis and a bit of arthiritis, she has some trouble getting up and lying down, some times she screams in pain while doing so….i have gradually reduced her meal portions considerably and put her on a special mobility diet. She is now slimmer but always hungry.

    Anyway, here’s some great news for all dog lovers – Cure for Canine Distemper – I have seen it save 3 dogs personally, saved one of mine : http://kindheartsinaction.com/
    Please help spread the word!

    Warm regards,

  2. Hi Kaveri

    I just started my 11 year old shepherd on the medication to treat incontinence – How is your dog doing now ?

  3. Hi,

    My 10 yr old GSD Natli has been on DES since the past 5 days as she has been wetting herself since many years. We tried many things such as Ephidrine tabs, Nutrivet Bladder control pills, but they stopped working after a few months. The vet says that she probably got immune to them.

    DES is working so far for Natli and she hasn’t wet herself since she’s been taking it. I am also giving her a course of anti biotic to get rid of any sort of infection.

    I just want to know what if there are side effects of DES for dogs. I am reducing the dosage to 1mg twice a week.


  4. so… my vet would like me to give this to my dog.

    I am a lactating female who is planning another pregnancy. Are there any special precautions I should take when handling pills?

    (You can thank the propecia ads for wierding me out about this!)

  5. My dog has just started taking stilbestrol and has had a allergic reaction to it.
    Where can I get more info on allergic reactions in canines?

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