How To Mix & Administer Feline Birth Control

WARNING! This section deals with the mixing and preparation of prescription medicine for feline birth control. If you are not skilled in simple measurements and basic math, then do NOT proceed with mixing your own feline birth control.

If you have obtained a prescription for MA from a licensed veterinarian and you are unsure of proper mixing ratios, then consult with your vet to learn about proper mixing of MA. We assume no responsibility for mistakes caused on your part. This information is provided for educational and informational purposes only!


In the original Topix discussion thread many feral cat caretakers were in a dilemma when Feralstat disappeared from the market. They knew that the main ingredient of FeralStat was megestrol acetate, they just didn’t know the proper amount in each dose.


Lots of speculation was made about the proper amount per dose. Finally in early Autumn 2011, a website was found that listed proper dosages of liquid megestrol acetate  to prevent estrus in feral colonies. The website belonged to the Fairchild Foundation in Pennsylvania. Fairchild Foundation is a non-profit organization that is devoted to T-N-R of feral cat colonies. The veterinarian at Fairchild, Dr. Jennifer Fry, DVM, posted a chart on their website of proper mixing ratios of liquid Ovaban/MegAce for feral colonies. You can see the chart HERE. Notice that Dr. Fry says that they have been safely using a liquid suspension of MA for over 10 years—this was way before Feralstat was even brought to the market by Dr. Caltabiano.


Once users on the Topix thread discovered this information from Dr. Fry, then they were all able to make up their own liquid suspension of MA by crushing MA pills and dissolving them in distilled water. Some users emailed Dr. Fry and  she gave her expert advice on the use of MA to prevent estrus in feline colonies. Fairchild’s website can also be a valuable tool for you to show your veterinarian if he/she is reluctant to prescribe MA for you.


Please do NOT email Dr. Fry asking for a prescription for MA. She cannot do it unless you are a patient of hers. Please reference our page on this site on how to obtain MA.


If you find any of the information on this web site useful, please consider making a donation to Fairchild Foundation. Without their help, we may never have known the proper ratios of mixing MA for feral colonies. Our thanks go out to Dr. Fry and Fairchild Foundation.


We will now proceed with proper mixing of MA and we are assuming that you have already obtained MA either in tablet form or liquid MegAce form.






Are you using Megestrol Acetate tablets or liquid MegAce?


 If using Megestrol Acetate TABLETS click HERE.


If you purchased a bottle of liquid human MegAce, click HERE.

I will try to make this as easy to understand as possible. If you still are unsure and do not understand the mixing procedure, please get someone that can help you. You can also consult with your vet by having him reference this website. Do NOT use the old Topix thread as a guideline for dosing! That thread is dated. We are using the latest known dosing guidelines on this site.

Mixing & dosing guidelines