What are some natural insect repellent alternatives to DEET?

I hate DEET. I feel physically ill when I use products with DEET in them—like my skin is burning off. Plus, I am going to be backpacking in the Sierras and would like to make as little environmental impact as possible.

I know there are various essential oils that work naturally as insect repellents. Burt’s Bees also makes one. Would anyone recommend it, or another one in particular?

Remember, I’m going to be in the Sierras in the middle of summer…AH mosquito heaven!

Also, not so into taking garlic pills, they haven’t worked so great for me in the past…I just smelled like garlic.