We put tea tree oil in a dog shampoo, so read our answer with that in mind. Concentration and species decide everything: 443 documented poisonings from 100% oil, and a different picture entirely for a dilute rinse-off wash.
Topic
Natural Dog Shampoo
We sell paraben-free dog shampoo and we used to tell you parabens were dangerous. On checking, there is no canine evidence for that at all. Here is what the label questions actually come down to.
Soap, liquid shampoo, or a natural shampoo bar — what's actually in each one, and which is the right choice for bathing your dog without damaging their skin.
We used to say dog skin has one layer and is three times thinner than yours. It isn't true, and we have withdrawn it. Here is the honest case for a dog-specific shampoo.