Earlier quoted context omitted.
Caffeine and nicotine are pesticides that humans have metabolic pathways to deal with. Dogs, for instance, can't handle theobromine.
tobacco 'tea' is a very effective pesticide, and is pretty easily removed by water. Great in dry areas, less so in rainy ones.
Be very, deadly careful not to get it on your skin. You can hit LD50 pretty quickly by dousing yourself in liquid stimulants.