[Harmless Teddy Bear]

Most of the "is toxic to animals" is people being stupid. Everything is a deadly poison when they are in high enough doses. Seven drops of tea tree taken internally will harm a cat.

But who in their right mind is going to give a cat that much pure essential oil at one time?

In fact do not give any pure essential oils to your pets. At all.

Fifteen drops in a quart of water sprayed around the house will not harm them at all even if you use the entire bottle at one time. Which you won't. A bottle lasts about a month around here.

[Nik Naym]

Tea tree oil, even on the skin of a cat, will kill it.