A myocarditis can occur both in the context of infections and as a result of non-infectious diseases such as sarcoidosis. In a large part of myocarditis caused by infections, the disease heals spontaneously. However, in a small proportion of patients with myocarditis, there is a chronically progressive disease with a consequent disturbance of the myocardial function corresponding to the clinical picture of a dilated cardiomyopathy. The gold standard for the diagnosis of myocarditis is still the endomyocardial biopsy. It is important that the myocardial biopsy is analyzed histologically, immunohistologically, and virologically using molecular biological techniques in order to accurately capture the various entities of myocarditis and then be able to initiate possible causal therapy options. Immunomodulatory and antiviral approaches are available as causal therapy options.