Mama Juana: a mixture of bark and herbs left to soak in rum, red wine and honey.
Additionally, other imported drinks are available for purchase--at least in the towns and cities--they might not be as readily available out in the countryside.
Do not drink tap water! Locals, even in the most rural areas, will either boil their water or purchase bottled water. Eating salads or other food that may be washed in tap water is not advisable. Ice is a bad idea as well, except in luxury hotels and restaurants which produce ice from bottled water. If you plan on cooking or washing dishes for longer stays, it is a good idea to rinse everything with bottled or boiled water before use. In every community, there will be one or more colmados the same as what are called bodegas in Puerto Rico where you can buy small amounts of everything. Water is sold in bottles at 15 pesos and up; it is also sold in plastic bags fundas at 2 for 5 pesos. But the best way by ecologic and economic means to buy drinkable water in Dominican Republic is to buy whole botellon - which is BIG, refilable bottle of water. It costs 50 pesos for refil of 17 litres 5 galons, and the cannister botellon itself costs around 200 pesos. But if you stay somewhere you for few days, you may ask the guys that you will buy it just for few days and they will give you back the money for the cannister.