A high-flow low-pressure irrigation system (10) for directing a fluid to and recovering the fluid from an area within a body, the irrigation system (10) comprising a sheath (37) and a flexible catheter (20) disposed in the sheath (37). The catheter (20) comprises a plurality of apertures (26) at a distal pigtail portion (28). The fluid is directed through the apertures (26) and recovered through the sheath (37). Renal applications include alkaline irrigation for dissolution or uric acid stones, chemo-dissolution of cystine stones, irrigation with chemotherapy drugs after ureteroscopic tumor management, antibiotic irrigation for severe infection (e.g. fungal and bacterial), and irrigation of thrombotic agents (Alum Or direct delivery of Amicar for renal bleeding).