The problem with essential oils and pets is that, truthfully, there have not been enough studies done on it, and vet's don't have them come to mind when something is wrong with a pet.
So, I take what studies have been done, things repeated over the years (I'd rather be safe than sorry, even if later something is proven to be untrue.), and my own experience and logic, and hope that it will be enough.
Here are my thoughts.
First, precautions. I keep my essential oils, of which I have quite a few now, in wooden essential oil boxes, then keep these up away from the dogs. The cats can't get in them, even if they wanted to - and I can't imagine them wanting to, and they are too heavy for them to push to the edge and over, for the dogs. Unlike the cats, I wouldn't trust the dogs at all. They shouldn't want to get at them, either, but if they did decide that a wooden box would make a good chewy, they could possibly get into the boxes.
Second precaution - I don't diffuse in a room that the cats, especially, are sleeping in, or when the door is closed. I want them to be able to leave if they wish, and prefer that they are napping elsewhere, even if it's an oil that I feel is okay for them to be around.
If you can smell things, there are particles in the air. If there are, then they can, conceivably, have it on their fur, and because they clean their fur so often with their tongues...well, you get the idea.
Animals get used to odors, and will sleep through them if they are in the air all the time, but with their noses being as good as they are, I also like to think that it's not fair for me to make them breathe in something that, to them, must be a very strong scent. I know that I don't like to be around a gallon of cologne on someone. So, as I say, I try to plan around it.
After meal time turns out to be a good time here, because the critters are rooting around the kitchen, the dogs go out, and they can sack out in the living room for a while. Over time I've noticed that they don't leave if I diffuse, but don't come in if they were in another room when I started. Unless something that they just have to be around is going on, or they think it's going on, of course!
I clean with essential oil based cleaners part of the time. And, during flu season, I make a concentrated mix to wash down things like the telephone. It helps. But, I am especially careful about 2 things.
A - I don't wash pet dishes with them. If someone is truly sick/contagious, I'll bring out the bleach. If not, my normal cleaners do the job well.
B - Because I mop with oils in the water about 1/2 to 2/3 of the time, I don't use anything that they can't be around, and I put them in the bedroom or outside...depending on who we're talking about, until the floor/s are done, and completely dry. I don't want it on the pads of their feet, nor do I want anyone tempted to lick at something damp...which they will.
In fact, if it's a big cleaning day, windows, etc. I prefer that they be in another room or outside anyway. That fresh, clean smell starts out pretty strong, even if it's just vinegar, alcohol, etc. based.
When I make products like my wet wipes (I have Tupperware baby wipe containers, buy dry wipes, put the dry wipes into the container, make a liquid mix, pour it over them, and voila! Wet wipes with varying uses...to clean quickly, to be anti-fungal, to just smell good and be refreshing, etc.), I kick everyone out, then make them. Once everything's laid out and ready to go, each container takes 2-5 mins., max.
And, like any product or food, what's okay for us, may not be good for the dog. And, what's good for us and the dog, may not be okay for the cat.
Also, I never did diffuse oils when I had birds, or in the same room with fish. That would probably be a good guideline for frogs, and other small critters, too. I used them on my skin, breathed them directly from the bottles, and cleaned in the rooms that they weren't in, but that's all.
Some of my go-to oils are lavender (triple check that it's not lavendin if you want to use it on broken skin/cuts/burns. I have tried several lavenders over the years, from 'wild' to ones which are derived just from flowers, or leaves. My usual use lavenders, interestingly, are not the more floral, though I use them, too, just less often. Lavendin is a cross of angustifolia, and has a higher camphor content. Not a bad thing for cleaning, but less desirable with cats, and small fuzzies.), sweet orange, tangerine, eucalyptus, ginger...there's more than one. One I love, one I hate...and others.
But, while I love a good sweet orange as a pick-me-up when going out, and use lemon and tangerine, it seems to be generally understood that citrus oils aren't good for cats, especially. So, I don't diffuse them. I do put them on my skin in the form of oil, and do add them to things that I make, such as certain wet wipes, or lotion. (Btw, you can make a neutral lotion, and add whatever oil you like to the amount you use each time.)
And, that being brought up, citrus is only good for people with a warning, which is: When you use some citrus oils, you have to be careful of the number of drops, which ones they are, and how they are derived, as they can cause varying degrees of photosensitivity. So, for example, I don't add any citrus oils to the wet wipes that I make for Ds to have in his truck, as he's out in the sunlight for work.
And, while it appears that oils such as thyme, oregano, wintergreen and peppermint are not pet friendly, they each have important properties for me. So, I don't diffuse them, once again, but will use them in what I use on my skin, or to spot kill real germs, depending on the oil and case.
A word about wintergreen. It is safe to use in small amounts, very small amounts, and is one of the ingredients in that gel that I use. But, overall, is not safe, because uncut, out of the bottle, it's way, way, way too strong. A teaspoon is the equivalent to something like 90 baby aspirin. So, most people don't need pure wintergreen around the house, especially if they have pets, or children will be around.
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