Mains water is normally chlorinated and, whilst relatively safe, if you have a sensitive stomach, you may want to drink bottled water rather than risk abdominal upsets. Milk is pasteurised and dairy products are safe for consumption. Local meat, poultry, seafood, fruit and vegetables are generally considered safe to eat.
Vaccinations against tuberculosis and hepatitis B are sometimes recommended. Sea swimming around the islands is generally considered safe, but watch out for strong currents; there are usually warning notices in place when this is the case. Anse Intendance, Anse Takamaka and Grand Anse are known to sometimes have dangerous tides and currents.
Being so close to the equator, the sunlight can be very strong; be sure to use sunscreen, keep hydrated and stay out of the sun between the hours of 1100 and 1500.