Thrombi occurring in heart chambers, particularly in the left ventricle, are very often due to diseases leading to heart dilation. Thrombi could dissolve spontaneously or as a result of pharmacological treatment. They could also be mobilizes and produce emboli. The risk of emboli vary significantly from low to extremely high due to different morphology and mobility of thrombi. The most effective treatment of thrombi is to cure the underlying disease. Additionally antithrombotic agents or surgical treatment may be applied. In this article 4 cases with different clinical course treated only with drugs are presented.