You have to take quite a large dose over the 4g/day limit for it to be lethal (unless it's mixed with a load of alco-ma-hol), and even then you would need to be young and in a pretty poor nutritional state. Unfortunately, since most parasuicides are young girls (who, on the whole, are often unnecessarily concerned about their weight and thus dieting and thus a tad malnourished), then accidents can happen and a cry for help/attention ends up with another senseless death.