Are lizards which we see in house walls poisonous? If so is it fatal?

What is the first aid if consume food stuff in which lizard is found (dead or alive) ?

What species of lizard is it?

I think it must be "Varanus bengalensis"

You have 1 metre long lizards in your walls? Cool. (Are you sure you have the right species?)

 

According to this site that species are hunted for their meat and skins.

For many years Bengal and clouded monitors have been collected on a large scale for their meat and skins. The meat of this species is reputed to be particularly sweet and easy to digest and for this reason it is often given to invalids (Deraniyagala 1953).

 

They would probably pose less of a poisoning danger than mice would but food should be kept in sealed containers anyway. (To avoid droppings.)