Forchlorfenuron (CPPU), as a plant growth regulator or herbicide/pesticide, is widely used in agriculture worldwide. It is adopted by most farmers due to its high efficacy for boosting size and improving the quality of fruit. However, CPPU was implicated in, and gained notoriety due to an incident of exploding watermelon that occurred in 2011. Subsequently, the wider community became aware of the potential risks it posed to living organisms and the ecosystem. In this study, we evaluated the effects of CPPU on the survival, cardiac morphology and function, as well as hematopoietic system, of zebrafish (Danio rerio). Notably, CPPU (2.5-12.5 mu g/ml) induced cardiac morphology deformation, cardiac contractile dysfunction and erythrocyte reduction in zebrafish. Consistently, the mRNA expression levels of several cardiac and hematopoietic gene markers (myl7, gata4, mef2c, amhc, vmhc and gata1) were altered by CPPU treatment. In addition, CPPU caused cytotoxicity, cytoskeleton destruction and reduced corresponding proteins (Myl7, Gata4 and Mef2c) expression in H9c2 cardiomyocytes in vitro. Taken together, this study has identified the cardiotoxicity of CPPU in different experimental models and enhanced our understanding on the mechanism underlying the toxicity of CPPU to living organisms.