Tropical
Traveling can increase your chances of getting sick. A long flight can increase your risk for deep vein thrombosis. Once you arrive, it takes time to adjust to the water, food, and air in another place. Water in developing countries can contain viruses, bacteria, and parasites that cause stomach upset and diarrhea. Be safe by using only bottled or purified water for drinking, making ice cubes, and brushing your teeth. If you use tap water, boil it or use iodine tablets. Food poisoning can also be a risk. Eat only food that is fully cooked and served hot. Avoid unwashed or unpeeled raw fruits and vegetables.
If you are traveling out of the country, you might also need vaccinations or medicines to prevent specific illnesses. Which ones you need will depend on what part of the world you're visiting, the time of year, your age, overall health status, and previous vaccinations. See your doctor 4 to 6 weeks before your trip. Most vaccines take time to become effective.
Centers for Disease Control and Prevention
Felter's Materia Medica on Tropical
   The ripe fruit, dried, of Capsicum frutescens, Linné (Nat. Ord. Solanaceae). Tropical America; also cultivated in most tropical countries. Dose, 1 to 2... / The ripe fruit, dried, of Capsicum frutescens, Linné (Nat. Ord. Solanaceae). Tropical America; also cultivated in most tropical countries. Dose, 1 to 2 grains. Common Names: Cay... / ...of typhoid fever, with almost complete suppression of natural secretions, we would be at a loss without capsicum. It sometimes checks a congestive chill, and1
   ...e whole plant Euphorbia pilulifera (Chamaesyce hirta), Linné (Nat. Ord. Euphorbiaceae). A plant of tropical climes and throughout the gulf states of the United States. Common Names: Pill-bearing Spur... / ...It is also said to relieve dyspnea of cardiac origin and to be of some use in emphysema. It may be administered in syrup, if desired.1
   The root and stem of Brunfelsia (Franciscea) uniflora, Pohl (Nat. Ord. Solanaceae). A tropical American shrub. Common Names: Manaca, Vegetable... / The root and stem of Brunfelsia (Franciscea) uniflora, Pohl (Nat. Ord. Solanaceae). A tropical American shrub. Common Names: Manaca, Vegetable Mercury. Principal Constituents.A weak al... / ...than to the articular forms, acting best when there is dull, heavy pain, soft skin and the absence of fever. It is thought to act somewhat like guaiac.1
   The decorticated... / ...eeds of Hordeum distichon, Linné (Nat. Ord. Graminacee). Native of central Asia; cultivated in all tropical and temperate climes. Common Name: Barley. Principal Constituents.Maltose, dextrin, fatty... / ...and a medium for the conveyance of medicines into the bowels in dysentery. It is also a good gastric lenitive after acute poisoning by irritants.1
   The juice and outer rind of the fresh ripe fruit of... / ...us medica Limonum (Risso), Hooker filius (Nat. Ord. Rutaceae). Northern India, and cultivated in subtropical countries. Common Name: Lemon. Principal Constituents.A pale-yellow or greenish-yellow, f... / ...of large quantities of acidulated fluid. It also sometimes relieves sick headache, and a hot lemonade is a popular remedy to break up a cold.1
   The dried root of (1) Smilax medica, Chamisso and Schlechtendal; or (2)... / ...alis, Kunth, or an undetermined species; or (3) Smilax ornata, Hooker filius (Nat. Ord. Liliaceae). Tropical America, Mexico to Brazil. Dose, 30 grains. Common Names: Sarsaparilla; (1) Mexican Sarsapa...1
   The dried ripe seeds of Strophanthus Kombé, Oliver, or of... / ...s hispidus, DeCandolle, deprived of their long awns (Nat. Ord. Apocynaceae). West and east coast of tropical Africa. Dose, 1 to 2 grains. Principal Constituents.Strophanthin (C31H48O128 to 10 per ... / ...It has been reported useful in cases of mitral regurgitation with dilatation; mitral stenosis with regurgitation; regurgitation wi1
   ... fruit of Vanilla planifolia, Andrews (Nat. Ord. Orchidaceae). A native Mexican vine, grown in many tropical countries, but on a commercial scale in Guadaloupe. Dose, 1 to 10 grains. Common Name: Van... / ...to powerfully stimulate the sexual appetite. It is used chiefly as a flavoring agent for medicinal syrups and tinctures, confections, and pastry.1
   Veratrine, Veratria. A mixture of alkaloids obtained from the seeds of Schoenocaulon officinale, Asa Gray (Sabadilla officinarum,... / ... Asagrea officinalis (Chamisso and Schlechtendal) Lindley; (Sabadilla seeds) (Nat. Ord. Liliaceae). Tropical regions from Mexico to Venezuela. Description.A white or grayish-white, non-crystalline p...1
   The... / ...ried rhizome of Zingiber officinale, Roscoe (Nat. Ord. Zingiberaceae). Southern Asia; cultivated in tropical regions of Asia, Africa and America. Dose, 10 to 30 grains. Common Names: Ginger. (There ar... / ...may be added to pills to prevent griping and tormina; and the syrup is an agreeable vehicle for stomachic and sometimes for expectorant mixtures.1