Fleas, allergies, ear mites or yeast infections, for cats.
Will olive leaf powder treat all the things the extract will?
Answer: Yes, but it is more gentle than an extract.
Can you make an ear drop solution for yeast or mites in your cat's ear?
I have never tried this but olive oil is supposed to work in a cat's ear for mites. You could try making a strong olive leaf tea and dabbing that on the ear with cotton wool followed by some olive oil. Alternatively you could mix the tea in glycerine and try dabbing that on.
You may be able to extract some of the active ingredients by gently warming the olive leaf powder or crushed leaves in apple cider vinegar or glycerine for an hour or so. Then filter and dilute the resulting fluid 1:2 in water.
It will need some experimentation to get the consistency and strength right.
Can you give olive leaf to your cat internally to keep fleas away and stop itching and or allergies?
Yes, it tends to boost the immune system and reduce inflammation so it should help the skin with itching and allergies - if you can get it into the cat that is. It apparently helps with human head lice taken internally so it may also help with fleas.
Will it also kill parasites in the intestines or even heart worms?
In high enough doses it is reported to kill intestinal parasites. One would have to experiment to find a dose sufficient for this. I have no experience with heart worms so I would be guessing here.
Once again, if you can get the cat to take it there are health benefits to be had as the immune system keeps the whole body healthy. If this is compromised any number of health problems arise.