What is the ruling on gifts, medicine samples, and hotel invitations offered to doctors by pharmaceutical companies, and what is the ruling on disposing of them by selling or giving them away?

There is no objection to accepting a gift from a company if the intention is to advertise and test its products. However, if the gift leads the doctor to favoritism towards the company or to prescribing its medication unjustly, then it is considered a forbidden bribe. The gift belongs to the one who receives it, and he is permitted to dispose of it by selling or gifting it.