Food & Water
The first 200 miles south of the border you will pass many markets. Most of the stores in Baja Norte have a large selection of fresh and prepared food. Once you are in Baja Sur shopping gets more interesting. At L.A. Bay there are several tiny markets in the village. Punta Chivato has no food supplies and Cabo Plumo may have a limited supplies. La Ventana/El Sergento has about many tiny markets. In La Ventana you can get your basics at Pablo's market just across from the camping area but for a larger selection and lots of Gringo food drive to market at the northern edge of El Sargento and you will probably everything you need. Los Barriles has great stores and supermarkets and almost everything you would find in USA markets.
Unlike mainland Mexico the water in Baja is almost always from deep wells and is safe to drink. Still...if you are on a short trip, you don't want to take any risks. You can buy bottled water at most markets in 5 gallon carboys.
Eating in restaurants
Most of the restaurants are not a problem in towns. I would avoid the street-side vendors you will see on you way down. Their goods look and smell delicious but their facilities for keeping food cold are lacking. If you are driving down, I would wait for restaurant food until you get to your destination then ask local sailors and kiters where the best food is to be found.
Traveler's diarrhea is not as common in Baja as in mainland Mexico. In 37 trips to Baja lasting a total of almost 4 years, I have not experienced traveler's diarrhea but I have seen less cautious friends have trips disrupted. In Baja the water generally comes from wells not rivers so the problem is not as acute. Still it is best to drink bottled water unless you know the water from the tap is OK. In my experience, you are most likely to get traveler's diarrhea from eating at small roadside restaurants or stalls where refrigeration and sanitation are problematic.
Here is summary of the Centers for Disease Control recommendations for traveler's diarrhea. See your doctor for personalized and current advice on traveler's diarrhea.
Taking Pepto-Bismol prior to travel has been found to decrease the incidence of traveler's diarrhea. If you have kidney problems do not take Pepto-Bismol. The Centers for Disease Control recommends not taking Pepto-Bismol for more than three weeks.
The antibiotic Ciprofloxacin also has been found to decrease the incidence of traveler's diarrhea. However, Ciprofloxacin is only effective against bacterial infectious and some people should not receive this antibiotic. See your doctor regarding use of Ciprofloxacin.
Usually traveler's diarrhea improves in a day or two. For mild cases replace fluid losses by water, carbonated drinks, fruit juice, and clear soups. Drink two glasses of water, a sports drink, or soda after going to the bathroom. Keep eating meals during diarrhea. Bananas, bread, crackers, rice, and potatoes are best. Avoid milk and other dairy products, raw vegetables, and fruits other than bananas. Do not use alcohol, coffee, tea, cola, herbs, spices, or fats.
If the mild diarrhea does not improve in a few days, consider medication. For mild diarrhea take Pepto-Bismol. Before going to Baja ask you doctor about using Lomotil and Imodium (available in Pharmacias) since they can provide short-term relief. But, they can hide serious illnesses so do not use them for more than 48 hours. Also do not use them if you have a fever or blood in your stool. Instead, seek medical help in those cases.
For prolonged or severe diarrhea, seek medical help. If that is not possible, special oral-dehydration (ORS) formulas are recommended. The most effective formulas are those made from prepackaged oral-hydration salts (ORS) found in Pharmacias in Baja and can be obtained in the U.S. If you are going to a remote area, consider buying ORS for your first aid kit.
Mix the contents of these packets with potable water following instructions carefully. If necessary, you can make your own solution mixing: 1 quart of water; 2 tablespoons sugar; 1/4 teaspoon salt; and 1/4 teaspoon baking soda. If using these solutions is not possible, drink whatever non-alcoholic liquid you can.
See your doctor about using antibiotics such as Ciprofloxacin or Trimethoprim / Sulfamethoxazole since they may help. If the diarrhea does not improve in several days, if there is blood in your stool, or if you have a fever, see a doctor.
For more information, call the Centers for Disease Control (CDC) automated hotline (404) 332-4559.