The water in Martinique is safe, but no one drinks from the tap. (The reason most people give is that the pipes are old and deteriorated.) Follow their lead and drink only bottled water; buy it at a supermarket rather than paying exorbitant minibar prices. If you develop stomach bloating and pain, pharmacies have some good over-the-counter antispasmodic medicine. If it persists more than a week, then it's probably time for a doctor and a round of antibiotics. Always come armed with mosquito repellent; there have been some dengue fever scares in years past, usually during rainy season.