Results of supravital and post-mortem observation of embolic-thrombotic complications in dogs, in the course of endotoxaemia induced by pyometra and phlegmonous pneumonia due to infection with Pseudomons aeruginosa, or endomyocarditis caused by Staphylococcus aureus infection were described. Multiorgan embolic-thrombotic complications were diagnosed in all presented cases. Most probably, the complications developed due to thrombocytopoenia secondary to platelet activation and exacerbation of endotoxin-induced DIC syndrome. In all the dogs, a disturbed cardiac rhythm was diagnosed supravitally. The rhythm disturbances might reflect myocardial injury due to presence of bacterial endotoxins in blood. The myocardial injury was confirmed by histopathological examination.