Can a lithium overdose be fatal? or would it just make the victim sick?

Don't play Russian: Roulette. You have received an answer from both me and from dr. Ali. I have seen both outcomes. The more common outcome is severe lithium intoxication with central nervous system side effects and with kidney failure. Of course death can occur. However, you are really playing russian roulette with this one because of the fact that the body often rejects it due to its extremely irritating effect on the stomach. The person who ingests it then typically vomits but doesn't vomit up enough to prevent the other toxicities mentioned above. Do yourself a favor and go to the emergency room and get help. It is not worth risking life of misery or losing your life. As i told you before you don't deserve to die.