Thrombocytosis is a medical condition characterized by an abnormally high number of platelets in the blood. Platelets are small blood cells that help with clotting, and an excessive amount can lead to an increased risk of blood clots, which can result in serious health complications such as stroke or heart attack. Thrombocytosis can be either primary (due to a problem within the bone marrow) or secondary (resulting from another underlying condition, such as inflammation, infection, or cancer). Treatment for thrombocytosis typically involves addressing the underlying cause, such as managing an infection or treating a blood disorder.