Transient and permanent myocardial damage is a vital element of toxicological practice. This applies both to poisonings in which heart injury is typical and to those in which it is only a rare complication. Vital signs of poisoned patients, especially unconscious ones, must be carefully monitored, because the consequences of late diagnosis or improper treatment can be potentially fatal. The following paper discusses the mechanisms leading to heart damage in the course of acute poisoning. It also presents clinical symptoms, treatment options and prognosis for myocardial injury in selected poisonings.