Many different medications can trigger immune thrombocytopenia, and the resulting clinical manifestations can be quite varied. Some patients are asymptomatic, while others have severe bleeding. Other complications include thrombotic microangiopathy manifested as hemolytic uremic syndrome (HUS). In patients sensitive to heparin, the most important complication is arterial or venous thrombosis. In this presentation, leading investigators will discuss work performed in their laboratories and by others to advance the understanding of pathogenesis and improve diagnosis of this group of conditions.