It's a good idea to pack one of these medications in your luggage, but the purser's office will have the tablets available. Avoid alcohol when taking these medications. If motion sickness has been a problem, you might want to see your doctor about a prescription for a seasickness patch. If nothing else works, see the ship's doctor. Be aware that a charge for doing so will be added to your account.
Most ships carry a physician and have a small infirmary for minor ailments.
In the case of an emergency, dial the help number listed on the cabin telephone. For serious medical conditions, airlift service to the nearest medical facility will be arranged. Check with your medical insurance for coverage limits and procedures. Check with the cruise line and your travel agent when you book. Arrangements for oxygen use or dialysis can sometimes be made.