How To Mix Feline Birth Control


If you are using megestrol acetate tablets that contain 20 MG each tablet (these are the most common), then you will need to follow the guidelines below. It is best to make a LIQUID SUSPENSION out of the tablets as this will make it easier to dose a colony. Remember the guidelines below are only for 20 mg tablets. If your tablets are 5 MG tablets, then you will need to go HERE.


To make a liquid suspension of feline birth control, you will need the following:


(2) 20 MG each megestrol acetate tablets


8 ML of distilled water

A pill crusher

A sterile dark/amber bottle to store solution in

A needleless syringe to measure ML

Step 1: Thoroughly crush the (2) 20mg each  MA tablets NOTE: If by chance you are using 40 mg tablets instead of 20 mg tablets, crush only ONE of these 40 mg tablets. Always wear latex gloves when handling the pills.


Step 2: Dissolve the crushed pills into the 8 ml of distilled water and shake well.

You have now created a liquid suspension that contains 40 mg of liquid MA(2 pills x 20 mg each = 40 mg)


Since you dissolved the (2) 20mg each pills into 8 ML of distilled water, your final product is one which is 8 ML of liquid containing 40 mg of MA.  Each ML of this solution contains 5 MG of megestrol acetate. (40 mg divided by 8 ml water = 5 mg per ml of liquid.)


Shake this solution well before each use as the MA tends to settle. You are now ready to dose your feral cat colony using this liquid suspension that you just created.


Use the chart below for proper dosing of the liquid suspension. DO NOT OVERDOSE! Use an accurate syringe (no needles!) with ml markings to be sure of accuracy. Follow the chart below exactly!



Chart for dosing feral colony using the liquid suspension as outlined above:


Total Number of Cats in the Colony - Dosage per colony / Frequency  


LESS THAN 5 cats: 0.5 ml ONCE a week (NOTE DECIMAL HERE! 0.5 ML! NOT 5 ML!)

5-7 cats: 1.0 ml ONCE a week

8-11 cats: 1.5 ml ONCE a week

12-15 cats: 1.0 ml TWICE A WEEK

16-19 cats: 1.5 ml TWICE A WEEK

20-23 cats: 1.6 ml TWICE A WEEK

24-27 cats: 2.0 ml TWICE A WEEK

28-31 cats: 2.2 ml TWICE A WEEK

32-35 cats: 2.5 ml TWICE A WEEK

36-39 cats: 2.8 ml TWICE A WEEK

40+ cats: 3.0 ml TWICE A WEEK


1) This medication MUST be mixed in CANNED cat food & served on multiple plates or dishes (NO PAPER). Use one 5.5 oz can of cat food for every 3 cats in your colony. It is very important to spread it out on as many plates as possible so the entire colony is being medicated as evenly as possible.


2) Shake the bottle of medication vigorously as the MA/Ovaban settles to the bottom. It is very important that the MA/Ovaban is mixed thoroughly before dosing to avoid under/overdose. Divide the appropriate dose of medication for your colony evenly among the plates of food and mix it thoroughly into each plate of food.




4) Store medication with bottle tightly capped in a cool, dry place away from sunlight.


5) Wash syringe with dish soap and water. Rinse thoroughly. Allow syringe to air dry on a paper towel.

For colonies that require a frequency of 2 times per week, the dosages MUST be spaced out.


Use ONLY distilled water. The shelf life of the liquid suspension once mixed is about 2 years if kept out of sunlight and at a cool temperature. However, some MA tablets may contain lactose & other ingredients/fillers that may mold after a few days of mixing. If your liquid suspension molds from using tablets mixed with water, then use the DRY mixing method as outlined on the 10 MG tablet mixing page. If you are using the liquid MegAce rather than tablets to mix a liquid suspension, then your final  solution will indeed have a shelf life of about 2 years. Remember to always shake well before each use.






Mix your own feline birth control using 20 mg Tablets