My 3year old kid has recently developed a habit of putting everything in mouth., what could be the reason?

A. Thumb sucking in infants is a very normal phenomenon and its called mouthing reflex and nothing to be worried about it just maintain proper hygiene and with time this thing will go . In the toddlers thumb sucking habit is also seen fmany a times which could be phycological cause and feeling of insecurity or some stress . Just try to make the child comfortable anvfd divert in some activities also spend good time with the child . In extreme case withdrawal can be tried with some solution available which are bitter like femite lotion . It needs to be applied locally .