A 58-year male was referred to our centre with an acute inferior ST elevation myocardial infarction (STEMI). During the primary percutaneous coronary intervention, he suddenly collapsed with severe hypotension and severe bradycardia. The symptoms were attributed to an accidental embolisation of his left coronary system with the thick contrast material. When the remaining contrast in the bottle was investigated, it contained abnormally thick contrast material. This is a rare case of contrast embolisation, which is completely preventable but fatal, if undetected. Key Words: Coronary angiography, Contrast material, Contrast embolisation.