Man's relationship with his environment has resulted in the development of a very rich traditional pharmacopoeia based mainly on medicinal plants. In Algeria, the plants uses are also oriented by scientific knowledge inherited from Muslim civilization in the books of Rhazes, Avicenna, Dawud El-Antaki, Ibn Beitar and Ibn Hamadouch. The infectious diseases known in the eighteenth and nineteenth centuries were treated by therapeutic formulas made from a plant, a mixture of plants or a mixture of plants and inorganic ingredients. Therefore, therapeutic formulas have been developed to treat measles, smallpox, urethritis, syphilis, malaria, tuberculosis, impetigo, scabies and yaws whose treatment has been imported to other countries and used successfully. These treatments can be prepared by infusion, decoction, maceration, trituration, fumigation, cooking and administered in drinks, eye drops, baths, soft dough and ointments. Currently, natural extracts of medicinal plants rich in biologically active chemical compounds have proven their antimicrobial, antiviral and antiparasitic potential in in vitro and in vivo studies. The valorization of plant medical resources provides effective alternatives in the treatment of these diseases and against the resistance of infectious agents.