Haemodialysis is one of the modalities of extracorporeal renal replacement therapy. Extracorporeal renal replacement therapy is used in its intermittent form to treat end-stage chronic kidney diseade, while its continuous form is usually used to treat acute conditions, such as acute kidney injury, severe metabolic disorders or poisoning by certain chemical compounds. Haemodialysis is mostly based on a physical principle of diffusion to remove small solutes from blood but, in a smaller portion, also on principles of ultrafiltration and convection to remove larger solutes and extra volume from the body. Like any procedure used in medicine, there are sertain complications possible when utilizing haemodialysis, both chronic and acute. Acute complications are mostly caused by extracellular volume and electrolites shifts. The most common acute complications are usually mild and include nausea, vomiting, muscle cramps, hypotension. The more severe ones are dysequilibrium syndrome or hypersensitivity reaction to dialyser or blood lines. They are also far less common. The probability of acute complication ocurrance can be minimised. If it does ocurr, there is a range of procedures and therapies used to treat them. Experienced medical personnel and their knowledge of acute complications may greatly assist in minimising their incidence.