Due to the lack of medical officers, Savaresi was immediately drafted to the French army, beginning his career as an army physician. From 1796 to 1798 he took part in the first Italian campaign of the French revolutionary wars. From Rome he was dispatched to the "armée d’Orient" and participated in the conquest of Malta and the French campaign in Egypt (1798-1801), which was initially led by Napoleon Bonaparte. He served at Damietta, Cairo, Salhiya and Alexandria and during the battles of the Pyramids and of Abukir.