Skip to main content


Whether you’re planning a day trip, a weekend on the water or an extended coastal cruise, certain medical problems are likely to occur. Many conditions are preventable, and others can be treated on board well before they require more specialized medical care. Having some basic knowledge, together with a well-stocked medical kit and user-friendly guide to marine medicine, will go a long way toward having a safe, healthy and comfortable day on the water.

Minimizing time below deck will help reduce the sensory conflict that brings on symptoms.

Seasickness, or mal de mer, is certainly a boater’s most common and dreaded ailment; susceptibility is virtually universal. Untreated, seasickness leads to rapid physical and mental deterioration, posing a major hazard to crew health, safety and morale. During stormy weather, mariners frequently consider seasickness a medical emergency and summon an unnecessary and potentially hazardous medical evacuation. It is clearly an illness to be reckoned with.

Seasickness results from a mismatch of sensory input processed by the brain’s balance center to orient the body’s position. Place someone in the cabin of a heeling and rolling boat, and you immediately invite seasickness. Below deck, the eyes oriented to the floor and overhead detect no tilt from vertical, but fluid in the inner ear shifts with the boat’s motion, sending a different position signal to the brain. Position sensors in the neck, muscles and joints relay additional information depending on how the person moves and maintains balance.

The conflict of sensory data from all these sources ultimately activates a series of responses we recognize as seasickness, especially the intense nausea and vomiting. The trick to preventing seasickness is to avoid sensory conflict by coordinating the input, especially from your eyes and ears. Simply put: If your eyes are seeing what your ears are feeling, you are going to have a great day at sea.


Pretrip preparation should help minimize time spent below deck while under way. Avoid close-

focused visual tasks such as reading or navigating. Stay in the fresh air, away from engine fumes, and near the center of the boat, where the motion is less-pronounced. Munch on saltines and sip water or juice. Keep your eyes on the horizon to provide a stable reference point. Sit or stand upright with your head and upper body balanced over your hips, and anticipate the boat’s motion as though “riding” the waves. Standing and taking the helm will help you accomplish this. Steer the boat by reference to the horizon, clouds, oncoming waves and distant marks. This is extremely effective in reducing sensory conflict.

It may take as long as three days to adapt to the boat’s motion and get one’s “sea legs.” Medication and a variety of tactics are generally more effective in preventing symptoms than reversing them during this period of adaptation.

Start your trip well-hydrated, and avoid alcohol. Eat a light meal low in fat and high in starch. If you anticipate becoming seasick, begin medication the night before departure. Bonine, Dramamine and Phenergan are effective, as are other medications. Repeat doses at the recommended intervals. Sudafed or NoDoz can counteract the drowsiness caused by these drugs. The prescription Transderm-Scop adhesive patch, applied behind the ear two hours before departure, may cause less fatigue and will last for three days. Discuss the side effects with your physician before trying it. Scopace tablets allow sailors to regulate the amount of scopolamine to reduce side effects.

Alternative therapies, which may be beneficial, include ginger capsules, one gram every six to eight hours and supplemented with ginger cookies, candied ginger and ginger ale. The ReliefBand is a wristwatchlike device that delivers electrical stimulation to nerves in the P6 acupuncture site in the wrist. When positioned properly, the wearer will feel a pulsed tingling sensation across the palm and in the middle two fingers. An elastic band with a plastic stud that applies pressure to the same acupuncture site without electrical stimulation may also be effective for some boaters.

Image placeholder title

A variety of medications, devices and herbal remedies work for some people and not others. There is no magic bullet that will prevent seasickness in everyone. If one drug fails to work for you, try another; do not be afraid to try different medications or modalities on land to see if there are any unacceptable side effects. If you have discovered a safe system that works for you, stick with it and believe in what you use.

Symptoms and treatment

The earliest signs and symptoms are yawning and drowsiness, progressing to dry mouth, headache, dizziness and extreme listlessness. Some people initially experience an unsettled stomach, slight sweating, mild blushing and a feeling of warmth. Untreated, the person becomes pale, cold and clammy. Nausea comes in waves with belching, salivation and then uncontrollable vomiting. Recognize and begin treatment with prescription anti-nausea medication (e.g. Phenergan) when early signs appear. Phenergan — taken as a pill, suppository or injection — will prevent vomiting and subsequent dehydration. During treatment, lie down and try to sleep. Take small amounts of fluid, crackers and hard candy.

Sailors now have many options to manage seasickness. It is no longer necessary to follow Samuel Johnson’s 18th century advice: “To cure seasickness, find a good big oak tree and wrap your arms around it.”

Dr. Michael Jacobs is co-author of “A Comprehensive Guide to Marine Medicine” and author of numerous articles and chapters on medicine for mariners and safety at sea. He is the founder of MedSail and teaches marine medicine around the country. A lifelong sailor, he practices medicine on Martha’s Vineyard, Mass.

For more on seamanship & safety, go to

This story first appeared in the January 2009 issue.