Nonbacterial thrombotic endocarditis (NBTE) is a rare but serious condition that affects the heart valves. It is characterized by the formation of small clots on the heart valves, which can lead to the obstruction of blood flow and increase the risk of embolism and stroke. It is also known as marantic endocarditis, sterile endocarditis, and Libman-Sacks endocarditis. Although the exact cause of this condition is unknown, it is commonly associated with underlying autoimmune diseases or cancer. Treatment for NBTE often involves managing the underlying condition, as well as anticoagulant therapy to prevent clot formation and embolism.