Common cruise ship illnesses — stomach bugs or seasickness — can ruin your vacation. Ship crews typically include at least one doctor, while the largest ocean liners have a full staff of doctors and nurses. Basic medical care is always available, as well as defibrillators and supplies to treat broken bones. But always bring a sufficient supply of your regular medications on any trip. Although not every cruise ship illness is avoidable, many are easily treatable. Familiarize yourself with the following five tips to avoid a cruise ship illness.

Lessen risks of overexposure and skin cancer with SPF and protective clothing. — Photo by Getty

Overexposure
The ocean magnifies the sun's rays. Protect yourself from sunburn by liberally applying sun block with a high SPF. A sunhat provides much needed shade on your ship's deck, while breezy long sleeves or a wrap keeps you cool but covered from the sun. Even when the sun is not shining brightly, UVA and UVB rays can still harm your skin and cause sunburn. Skin cancer is a very real risk after years of such sun exposure.

Although saltwater can be beneficial for many skin conditions, swimming pool water can be harmful. Chlorine dries out the skin and can worsen skin conditions such as psoriasis. Pre-treat dry skin with Vaseline and apply moisturizers after swimming. Although chlorinated pools are supposed to have low levels of bacteria, chlorine can't kill off every bug. Bacterial contamination in swimming pool water can cause stomach illnesses (see "Stomach bugs" below). Avoid swallowing pool water — especially in the kiddie pool!

Stomach bugs
Gastroenteritis, an ordinary stomach bug, is difficult for cruisers to avoid and is a common cruise ship illness. In fact, it's one of the most common diseases among travelers around the globe — be they cruisers, fliers or drivers. Chances are you'll be exposed to a virus or bacteria on your dream vacation, especially if you happen to be on a ship with contaminated food or infected people. The basic rules of food hygiene apply: Wash your hands frequently, especially before meals; eat only food that is thoroughly cooked; and practice moderation on the buffet line.

Norovirus is a common culprit of stomach sickness. This hardy organism requires little growth to cause illness, resists many sanitation procedures and is transmitted easily between people. Other bugs such as E. coli, salmonella, staphylococcus, shigella and hepatitis are potentially serious diseases. Always inform your ship's doctor at the first sign of any illness. If you suffer from diarrhea or vomiting on your cruise, drink lots of water to stay hydrated.

Next: Curbing motion sickness and steering clear of tropical diseases. »