Can I mix food colouring to make brown, for icing?

[BusyMissIzzy]

Local Sainsburys doesn't have brown food colouring, but had red and green. Can I mix them, like paint? I need brown monkey-coloured icing :)

I would use chocolate.

Yes, you can mix them. It should be fine.

On the other hand cocoa powder would work well too.

You just put cocoa powder in with the icing sugar.

I would use chocolate, but it's a banana and pineapple cake so I'm not sure chocolate would taste right.

Ummm maybe blue and green?