Blebbistatin is a myosin inhibitor mostly specific for myosin II. It is widely used in research to inhibit heart muscle myosin, non-muscle myosin II, and skeletal muscle myosin. It has been especially useful in optical mapping of the heart, and its recent use in cardiac muscle cell cultures has improved cell survival time.

However, its adverse characteristics e.g. its cytotoxicity and blue-light instability or low solubility in water often make its application challenging. Recently its applicability was improved by chemical design and its derivatives overcome the limitations of the original molecule. E.g. para-nitroblebbistatin and para-aminoblebbistatin are photostable, and they are neither cytotoxic nor fluorescent.