Low-viscosity, high concentration nucleic acid compositions that can be administered by multiple parenteral routes may allow for less frequent dosing than nucleic acid products currently on the market. In particular, low-viscosity defibrotide formulations for subcutaneous, intramuscular, and intraperitoneal administration are more convenient to the patient and/or are administered outside of the hospital setting. Formulations of the invention may be used for the treatment of numerous conditions including for example, treatment of peripheral arteriopathies, treatment of acute renal insufficiency, treatment of acute myocardial ischemia, and treatment and prevention of sinusoidal obstruction syndrome or VOD.