Nasturtium has long been used in Andean herbal medicine as a disinfectant and wound-healing herb, and as an expectorant to relieve chest conditions. All parts of the plant appear to be antibiotic and an infusion of the leaves can be used to increase resistance to bacterial infections and to clear nasal and bronchial catarrh. The remedy seems to both reduce catarrh formation and stimulate the clearing and coughing up of phlegm. The leaves are antibacterial, antifungal, antiseptic, aperient, depurative, diuretic, emmenagogue, expectorant, laxative and stimulant. A glycoside found in the plant reacts with water to produce an antibiotic. The plant has antibiotic properties towards aerobic spore forming bacteria. Extracts from the plant have anticancer activity. The plant is taken internally in the treatment of genito-urinary diseases, respiratory infections, scurvy and poor skin and hair conditions. Externally it makes an effective antiseptic wash and is used in the treatment of baldness, minor injuries and skin eruptions. Any part of the plant can be used, it is harvested during the growing season and used fresh. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Tropaeolum majus Nasturtium for urinary tract infections, cough, bronchitis (see for critics of commission E). Source: https://pfaf.org/
Find more about this plant on Wikipedia.