Egg Shells are not poisonous.
In fact Egg Shells are completely edible and can provide you with calcium if you do eat them or swallow some egg shells.
Egg Shells are not very appetizing but they are indeed edible and you can eat them if you want too but it would be best to grind the egg shells up in powder form to consume them to avoid choking on them.
it's not a bad thing to swallow egg shells.
Even though egg shells are not really very appetizing it's actually healthy for you to eat and swallow egg shells.
The egg shells provide you with calcium which is good for strong bones so your health will actually improve or should improve if you eat egg shells.
But I would not want to eat egg shells because they are very crunchy and hard to chew and could pose a choking hazard.
But you could probably grind the egg shells up into a powder form and take them that way to get your calcium intake.
But if you do swallow some egg shells or pieces of the egg shells it's not harmful.