Coronavirus 2019 (COVID-19), the disease associated with infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in December 2019 (50) and is now the most significant worldwide public health crisis since the influenza pandemic of 1918. Despite this immense global burden, no pharmacologic therapies have proven definitively beneficial (25). On the basis of our clinical experience in intensive care units in Colorado and those shared by the wider critical care community, we conclude that many therapies are being administered despite limited evidence. Anticoagulants that have been utilized widely are unfractionated (full-length) heparin and low-molecular weight heparins. For the purposes of this review, heparin herein refers to both unfractionated and low-molecular weight variants, unless otherwise designated.