It's imperative to plan your trip to Mexico. This section will cover what you need to know about planning a safe and relaxing vacation.

Pack Light or Heavy?

The kind of clothes you pack depends on where you go and the weather. Generally, Mexico is an informal country, so casual clothes are fine. Larger cities like Mexico, Monterrey, and Guadalajara may require something a little nicer for dining out in better restaurants. And don't forget to pack an umbrella and a lightweight raincoat if you plan on being in Mexico from May to October, during the rainy season.

If your travels take you to Mexico City or the central highlands during the winter months, the temperature can drop to the mid-20s at night. You'll want to dress in layers since the sun can warm things up during the afternoons.

Traveling with Little Ones

Mexicans love children and take their own everywhere. The family is the cornerstone of Mexican life. So hotels and restaurants gladly welcome little ones. Pace your travels keeping your child in mind. Avoid fast-paced tours, and keep travel time as short as possible. Kids love to visit zoos, markets, plazas, aquariums, and the like, so be sure to include some in your itinerary.

And don't forget that packing for your kids, especially toddlers, requires some additional items. While you'll find disposable diapers, baby food, and medicines available in larger towns and cities, you should remember to pack a lightweight folding stroller, papoose-style backpack, a life jacket and beach toys, and a car seat if you're going to drive anywhere. And don't forget some handwipes and extra plastic bags for dirty diapers.

Can You Drink the Water?

It used to be that just about everyone that traveled to Mexico got a case of Moctezuma's revenge, commonly called turista, from drinking water tainted with a form of E. coli bacteria. But in recent years, the Mexican congress has passed laws requiring anyone serving the public to serve purified water. However, according to a recent study by the Office of Medical Applications of Research, 20 to 50 percent of travelers to Mexico are still getting sick. Is it just the water? The answer is a complicated no.

The leading cause of discomfort, Escherichia coli, otherwise known as E. coli bacteria, can be ingested in food as well as water. While many attacks can be blamed on unpurified water, just as many can be caused by unsanitary food-handling and unfamiliar spices.

You should also refrain from drinking fancy alcoholic drinks and eating rich foods for the first few days. If you have to drink, Mexican beers and wines are best, served cold without ice. Remember that tequila sold and enjoyed in the United States isn't as strong as it is in Mexico. Plus, Mexicans drink slower than visitors, who often drink at the speed they're used to back home, not realizing the heat can affect them.

Even the Mexicans agree that one of the best solutions to turista is common Pepto Bismol (bismuth subsalicylate), either in liquid or tablet form. However, recent tests have shown that there can be severe side effects if this medication is taken too often. Another product, Imodium D, seems to work better and faster, without the accompanying side effects.

Episodes of turista begin abruptly, often without warning. They can occur during travel as well as after returning home and aren't contagious. The most common day of onset is the third day after arrival in Mexico, but onset may occur at any time during the visit and even after returning home.

Both cooked and uncooked foods may be implicated if improperly handled. Especially risky foods include raw vegetables, raw meat, and raw seafood. Tap water, ice, unpasteurized milk and dairy products, and unpeeled fruits are also associated with an increased risk of turista.

Depending on how long you go without treatment after the infectious bacteria have entered your digestive tract, the effects can be severe. So if it strikes, head for the nearest First Class pharmacy, with a pharmacist who speaks English or with a Mexican to interpret for you. This is no time to practice your Spanish. One of the best local medicines is a green chalky liquid sold under the name of Diarim.

Bottled water is available just about anywhere, even in the smallesttienda (shop). When in doubt, ask for agua purificada or agua minerale. Today, just about all restaurants serve bottled water. Better restaurants also use purified water for ice. And while the law requires all hotels to leave sealed bottles of purified water for their guests, you should know that five-star hotels will add as much as $3 a bottle to your bill if you open them.

Using purified water applies not only to drinking but to brushing your teeth and rinsing your contact lenses. Above all, wash your hands as often as possible, especially before meals. Always carry some disposable antibacterial handwipes for when you can't. It doesn't pay to get paranoid about getting a case of turista, but a little common sense goes a long way.