It depends, in part, on your destination.
In light of escalating drug-related crime in Mexico's big border cities, safety is a valid concern. In July 2013, the U.S. State Department issued an extension of its travel warning for citizens traveling to Mexico. According to the State Department, drug cartels are battling each other for control of the drug trade and simultanously fighting government attempts to crack down on their activities. The result has been an increase in violent crime in parts of northern Mexico. While foreign tourists aren't typically targeted, they occasionally find themselves in the wrong place at the wrong time.
Complicating the issue is the lack of news information coming from the affected areas; the cartels have begun to target Mexican journalists who report on drug-related murders, so some media outlets are not reporting on this issue. Unfortunately, the reports that do trickle back indicate that kidnappings, murders, robberies and other violent crimes are on the rise in border areas, particularly in the cities of Tijuana, Nogales and Ciudad Juarez. On occasion, foreign tourists and workers have been deliberately targeted. U.S. news sources, such as the Los Angeles Times, report ongoing violence, including armed robberies and exchanges of gunfire. The State Department strongly encourages U.S. citizens to "be alert to safety and security concerns when visiting the border region" and to monitor local news reports while traveling.
However, Mexico is a very large country, and there are many areas that are safe to visit. According to Suzanne Barbezat, About.com's Guide to Mexico Travel, "Most people who travel to Mexico have a wonderful time and don't encounter any problems." In most parts of Mexico, tourists need only exercise the caution that they would in any vacation spot – pay attention to surroundings, wear a money belt, avoid dark and deserted areas – to avoid becoming crime victims.
Mexico has much to offer as a vacation destination, including good value, a rich cultural heritage and stunning scenery. If you are concerned about the safety situation, avoid border cities, particularly Ciudad Juarez, Nogales and Tijuana, plan an itinerary that skips known trouble spots, check the latest travel warnings and be alert to your surroundings during your trip.