if it's pure, over 1000mg would be dangerous, but isn't that the nature of coke, danger, so don't die now on us.
it really depends on alot of other factors but a safe rule of thumb would probably be not to ingest more than 500mg, which begs the question if you have stuff strong enough to kill you, shouldn't u be able to get off from only a small amount, and if in the case you need to carry it around with you, just carry enough, not more, carry a few lines which should be less than 500mg, which in the case that you had to eat it to destroy evidence wouldn't you thank yourself for not going all out like charlie sheen. Unless of course your intention is to retail the substance, then you should probably not be doing that in the first place, and if you are caught selling it isn't any consequence therein totally justified by your irresponsibly? I have nothing against an individual using a substance that benefits them, but when the benefit is outweighed by the danger, then they ought to re asses their situation, and maybe just practice a little bit of harm reduction. be safe now