Is Birth Control Pills Toxic to Cats and Dogs?
Birth control pills are mildly toxic to dogs and moderately so to cats. Large amounts of estrogen can suppress bone marrow. Call a vet for guidance.
Can cause real harm — call a vet for guidance.
Usually minor, but watch for symptoms.
In an emergency, do not wait.
Medical disclaimer: This tool is for general information only and isnot a substitute for veterinary diagnosis or treatment. Toxicity depends on the amount, your pet’s size, and health history. If your pet may have ingested something harmful, contact your veterinarian or a poison control hotline ((888) 426-4435 / (855) 764-7661) immediately — do not wait for symptoms to appear.
What is Birth Control Pills?
Birth control pills are mildly toxic to dogs and moderately so to cats. Large amounts of estrogen can suppress bone marrow. Call a vet for guidance.
Also known as: estrogen, oral contraceptive, birth control, hormone replacement, estradiol, hrt, plan b, progestin.
Symptoms to Watch For
🐈 In Cats
- Vomiting and diarrhea
- Reduced appetite and lethargy
- Bone marrow suppression with larger amounts
- Pale gums or bruising in serious cases
🐕 In Dogs
- Mild stomach upset and vomiting
- Diarrhea and reduced appetite
- Rarely, bone marrow suppression with large or repeated amounts
- Estrogen toxicity (lethargy, bleeding tendency) only with larger doses
What to Do If Ingested
- Note the hormone type, mg strength, and number of pills eaten.
- Call a veterinarian or poison hotline for guidance.
- Watch for vomiting or lethargy.
Steps apply to both cats and dogs. When in doubt, call a vet or poison hotline before acting.
When to Call the Vet Immediately
Call your veterinarian or a poison control hotline right away if you notice any of these:
- A large number of pills, a transdermal patch, or hormone replacement was eaten
- Persistent vomiting or diarrhea
- Lethargy, pale gums, or bruising/bleeding
- Signs of estrogen toxicity (repeated doses)
Frequently Asked Questions
Frequently Asked Questions
My dog ate one birth control pill — is it an emergency?
A single birth control pill is usually low risk and may cause only mild stomach upset. The concern rises with many pills, transdermal patches (which are concentrated), or estrogen-containing hormone replacement, which can suppress bone marrow. Call a vet with the hormone type and number of pills.
What is the danger of estrogen in pets?
Large or repeated doses of estrogen can suppress the bone marrow, reducing red and white blood cells and platelets. This can cause anemia (pale gums, weakness), infections, and bleeding or bruising. It is more a concern with concentrated hormone products than a single pill.
Are hormone replacement therapy (HRT) and patches more dangerous?
They can be. Transdermal estrogen patches and high-dose HRT contain more hormone than a single pill, and a pet that chews on a patch can get a large dose. Treat ingestion of patches or HRT more seriously and call a vet right away.
Sources
This entry is reviewed against the following authoritative veterinary sources.
Last reviewed: 2026-07-11