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Rabbits/NOT urgent: Rabbit Needs Fenbendazole every 2 months. Is this safe?



Thank you for answering my question.

I'm a member of a Rabbit Rescue. My personal rabbit, a 3 year old neutered male Mini Rex Mix, has a highly sensitive digestive system. Any tiny bit of fruit or grains gives his gas.
Also, Patches contracted Pin Worms from a foster bunny that was found outside.

We have not been able to eradicate the pinworms, no matter what we've tried. The result is that Patches has to be treated for pinworms with fenbendazole every two to three months, once a day for three days. If I don't treat him, he gets gas every single day non-stop. Before we found the cause, he got gas every day for 16 days. He must have been so miserable.

My question is, is there a likely danger in giving fenbendazole every two months for life? If so, is there any dietary supplement that can help protect him?

Thank you so much!

Dear Bethany,

I know of many rabbits who are constantly on fenbendazole for E. cuniculi, and they don't seem to have problems related to the drug.  Some of the benzamidazoles are toxic to the bone marrow and can cause damage.  But of the three commonly used in rabbits, fenbendazole is one of the more benign.

If it keeps Patches happy and comfortable, I would not worry too much about using it once a month.



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Dana Krempels, Ph.D.


I've lived with companion rabbits for more than 35 years, and consider them members of my family. I can answer any questions about the biology and health of rabbits, from the commonplace to the unusual. But please note:

RULE #1:

Find a rabbit vet at for immediate help, and don't risk your bunny's life by spending time asking questions online! If you can't get in touch with your vet, read these Emergency Sick Bunny Instructions.

If you have found a wild baby rabbit, please read these EMERGENCY INSTRUCTIONS FOR WILD BABY RABBITS and then use this link to FIND A LOCAL WILDLIFE REHABILITATOR who can give you the right advice.

RULE #2:
Help me help you! Please make your subject line informative if you have an urgent question. then LET ME KNOW IN THE SUBJECT LINE so I can give your question highest priority over non-urgent questions. If you don't do this, then I can't guarantee timely assistance!

For all the best, most accurate rabbit health, care and behavior information, visit The House Rabbit Society.


I have been rescuing and rehabilitating domestic and wild rabbits for about 30 years. I have written articles for many rabbit rescue publications, as well as for the veterinary journal, Exotic DVM. I own EtherBun, the internet's largest listserve dedicated to health, care, and behavior of domestic rabbits.

Houserabbit Adoption, Rescue, and Education, Inc. (H.A.R.E., Inc.) president National House Rabbit Society (Board member)

Exotic DVM
Warren Peace (Journal of the House Rabbit Society of Miami)
Various newsletters of the House Rabbit Society, nationwide

Ph.D - Biology
B.S. - Biology
B.A. - English

Awards and Honors
Lightspan Academic Excellence Award for web site on rabbit health and biology

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