Intravenous drip. Image 3 of 4. Nurse adjusting the settings on an intravenous (IV) drip. This equipment is connected to a catheter (left) in the vein of a patient's hand. It is also connected at the other end to a drip bag (not seen), which may contain saline (water and salts) as a hydrating fluid if the patient is dehydrated or liquid medication if the patient is undergoing drug treatment. See M540/557-560 for a series of images showing the set up of an IV drip.