We get a fair number of people coming to this blog for the answer to that one, so we thought we’d address it briefly.
The answer is, ‘No.’ Not possible…not even from a whole box of pencils.
Why not? Because there is no lead in a pencil.
Yes, it is called ‘pencil lead’ but what it really is is graphite, a totally different substance from lead. Graphite is not a metal, but a mineral formed from carbon.
The graphite used in pencils is more or less harmless, as the US National Instute of Health explains on there website where they discuss the problems you may encounter if you inadvertantely swallowed a pencil.
So, getting stabbed with a bit of pencil lead, or swallowing some, is not going to give you lead poisoning. Of course, there would still be a hole in you from the stabbing, and swallowing bits of wood and other foreign material is a choking hazard, as well as a threat to your digestion.
Probably best just to use your pencil for writing.
(On a related note, you also cannot get ink poisoning from a pen.)