No such thing as vegetable based dye
The last few years have seen a bigger-than-ever push for natural and organic beauty products including hair dye.
Many consumers are under the impression that components found in "organic", vegetable based or "natural" hair products make them inherently safer.
Unfortunately it's not that simple. In fact, not only are these hair dyes not necessarily safer than synthetic hair dye, organic, vegetable based natural commercially made hair dye simply doesn't exist.
Other than henna, (which is not good for dogs anyway so please never use it) any commercially available hair dye — store-bought for home use or found in salons for pets or humans — uses chemical actives for them to work,” and most of the time these chemicals are synthesised substances.
Even when the packaging claims to be all-natural, organic or chemical-free — which is literally impossible because everything, including organic things, are made of chemicals — that could basically be an outright lie.
This is because the FDA (USA) and the MHRA (UK) can't do anything about the use of these terms regarding cosmetics. They regulate cosmetics via the Food, Drug, and Cosmetic Act and the Fair Packaging and Labelling Act, neither of which define the term "organic." In other words, if you see hair dye that claims to be organic, vegetable based or natural, it's "most likely still employing synthetic ingredients and chemicals for it to work,".
The good news: Hair dye doesn't have to be organic, vegetable based or natural in order to be safe, and there are other ways to be both health- and Eco-conscious when it comes to colouring hair.
As a general rule if the hair dye you want to use comes straight from the bottle and goes directly onto the hair it is safe to use. When you have to mix 2 products together before applying to the hair this is using a chemical reaction (oxidation) and will contain chemicals that could be harmful.
But there are many dyes specially made for pets now so if you’re unsure go for one of them.