@Jarkko uhhh, actually it's been proven that repeat drug or poison injection to the body decreases the drug/poison effects because the body become "immune" or tolerant to it over time. That's why people that drink a lot will take more time to get drunk, also applies to drug users.
@Narmaya- ignore them. They lacked the intelligence needed to recognize that myths and legends aren't exclusive to 1 thing. It's like those ppl who think everything is jojo ref.