Health & WellnessHow to combine and time Capstar, Advantage II, and DE for my cat?
Capstar works very quickly to kill adult fleas, but does not work longer than 24 hours. Advantage II will start working within 12 hours and will work for a month. I usually recommend a topical monthly preventative (like Advantage II) be applied every month. Capstar can be added in at any time if you see adult fleas, but will likely not be needed except for the first day. I have not had good success with diatomaceous earth, but it is safe to be combined with the other products. I can't give you a recommendation on frequency for that because I have not found that it makes a difference how often it is used.
Good luck! I hope that was helpful and answered your question. Thanks for using Petco Pet Education Center, formerly Petcoach.
Updated on September 24th, 2025
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