What hapens when i eat loads of mechanical pencil leads?

Non-toxic but test 4: Fortunately, pencil lead doesn't contain lead, a highly toxic substance, but is made of graphites, a form of carbon that is generally non-toxic. The big question is why are you doing this? Eating undigestible things like graphites is called pica ; is often a sign of lead or zinc deficiency, but can also be related to emotional problems. See http://www.Nlm.Nih.Gov/medlineplus/ency/article/001538.Htm.