How do you make poison?

Answer 1

Very carefully...

There are many poisons that we use on a regular basis.

Chlorine is a poison, but it is found in chlorine bleach. It helps make the bleach work. It is also used in pools to keep the water free of microbial organisms.

Rat poison, and insecticides are used to kill pests, but they are poisonous to us as well.

Sodium is a poison, and as noted above, so is chlorine, but together they make sodium chloride, usually called salt.

there are hundreds of other examples that could be given, but it would be impossible to include them all.

Answer 2

White Oleander does the trick. Or some arsenic. I would also suggest watching a few episodes of CSI. They tend to talk about untraceable poisons every now and then. Of course I don't support poisoning at all, this is just an answer to your question. I almost forgot, radiated bbs tend to do the trick as well.

Answer 3

You don't really. There are some elements in the periodic tables that are stunningly toxic -- for instance, plutonium 239 -- but of course they already exist.