Contaminated water should be an important concern for any tourist who doesn’t want to lose vacation days to illness.

Cholera, Hepatitis A, and typhoid are just some of the water-borne illnesses affecting parts of underdeveloped countries, according to clinical pharmacist Elizabeth Bunk, who administers vaccines and medications to travelers at Duquesne University.

Here are four ways to avoid getting an infection.

1. Use bottled water

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Travel health professionals strongly advise sticking to bottled, carbonated, and even canned water, and to refuse bottled water at restaurants if it’s brought to the table with the cap opened.

2. Avoid salads

Eating steamed, boiled or fried vegetables, instead of salads rinsed in water, also reduces the risk of illness.

3. Bring a prescription antibiotic

Consult with your doctor before your trip and ask for a prescription for a strong antibiotic, such as ciprofloxacin or levfloxacin, which can wipe out multiple types of bacterial infections that cause upset stomach and diarrhea. It’s wiser to come prepared than to try finding a doctor and pharmacy while abroad.

4. Use a purifier

In rural areas and smaller villages, purify water with iodine pills (except if you’re pregnant or have thyroid problems), or, alternatively, chlorine pills. For the most remote locations, water purifiers are the safest option. Try the Steripen Ultra, which has a UV lamp to kill bugs, microbes and bacteria. Or consider the Lifesaver water bottle, which uses nano-filtration to remove viruses, bacteria, cysts and parasites from contaminated water.