Travelers to Mexico need to guard chiefly against food- and mosquito-borne diseases. Besides getting the proper vaccinations, carry a good insect repellent and exercise care in what you eat and drink.
Private hospitals generally provide better care than public ones, but are more expensive: the best are in Mexico City. Your country's embassy or consulates in Mexico and the national tourism secretariat Sectur can usually give information on local hospitals, and some consulates provide it on their websites. You should have travel insurance that covers the cost of air evacuation to another country should you develop a life-threatening condition.
Make sure all routine vaccinations are up to date and check whether all vaccines are suitable for children and pregnant women.
Hepatitis A All travelers (except children less than one year old).
Hepatitis B Long-term travelers in close contact with local population (requires three doses over a six-month period).
Rabies For travelers who may have contact with animals and may not have access to medical care.
Typhoid All travelers.
Altitude Sickness May develop in travelers who ascend rapidly to altitudes greater than 2500m. Symptoms may include headaches, nausea, vomiting, dizziness, malaise, insomnia and loss of appetite. Severe cases can lead to death. To lessen the chance of altitude sickness, ascend gradually to higher altitudes, avoid overexertion, eat light meals and avoid alcohol. People showing any symptoms of altitude sickness should not ascend higher until the symptoms have cleared. If the symptoms become worse or if someone shows signs of fluid in the lungs (high-altitude pulmonary edema) or swelling of the brain (high-altitude cerebral edema), such as trouble breathing or mental confusion, descend immediately to a lower altitude. Descent of 500m to 1000m is generally adequate except in cases of cerebral edema.
Dengue Fever A viral infection transmitted by aedes mosquitoes, which usually bite during the day. Usually causes flu-like symptoms. There is no vaccine and no treatment except analgesics.
Malaria Transmitted by mosquito bites, usually between dusk and dawn. The main symptom is high spiking fevers. Malaria pills are recommended when visiting Chiapas or rural areas in Oaxaca, Sinaloa, Nayarit and parts of Sonora, Chihuahua and Durango states. The first-choice malaria pill is chloroquine. Protecting yourself against mosquito bites is just as important as taking malaria pills.
Snake & Scorpion Bites In the event of a venomous snake bite or scorpion bite, keep the bitten area immobilized, and move the victim immediately to the nearest medical facility. For scorpion stings, immediately apply ice or cold packs.
Mosquito Bites Wear long sleeves, long pants, hats and shoes. Don’t sleep with windows open unless there is a screen. Use a good insect repellent, preferably one containing DEET, but don’t use DEET-containing compounds on children under age two. If sleeping outdoors or in accommodations that allow entry of mosquitoes, use a mosquito coil, or a bed net treated with permethrin.
Sun Stay out of the midday sun, wear sunglasses and a wide-brimmed hat, and apply sunscreen with SPF 15 or higher. Drink plenty of fluids and avoid strenuous exercise when the temperature is high.
Water Tap water in Mexico is often not safe to drink. Purified water in plastic bottles is sold everywhere and is also available from large dispensers in some accommodations, which allows you to refill bottles. The most effective means of water purification is vigorous boiling for one minute (three minutes at altitudes over 2000m). Another option is a SteriPen, which kills bacteria and viruses with ultraviolet light. Pregnant women and those with a history of thyroid disease should not drink iodinated water.