An accidental intrathecal tranexamic acid injection is a rare but extremely unpleasant case, which can lead to severe complications, including death. This review aimed to describe the clinical, pathophysiological changes and outcomes occurring in patients with unintentional tranexamic acid subarachnoid injection during spinal anesthesia. The review includes studies published in PubMed, The Cochrane Library, Google Scholar, and the Russian Science Citation Index databases. There were 31 reports (27 literature reports and 4 own observations) of unintended tranexamic acid administration during spinal anesthesia, including 12 cases in traumatology and orthopedics, 11 cases in cesarean section, and 8 cases in urology and general surgery. Typical signs and symptoms reported by the authors include severe pain in the lower back, buttocks, and lower extremities, seizure syndrome, marked tachycardia and arterial hypertension, and ventricular arrhythmias. Ten (32.1%) patients recovered without any consequences and six (19.4%) patients required long-term rehabilitation after hospital discharge due to severe neurological deficits or cognitive impairment. Of 11 females, 9 died during cesarean section and 4 of 12 patients died in traumatology and orthopedics. Overall, 15 (48.4%) patients had a fatal outcome. An unintentional subarachnoid tranexamic acid injection is a catastrophic event with extremely high patient risk and is accompanied by high mortality, especially in obstetric practice. Intensive care should include intravenous propofol or sevoflurane inhalation in the case of unintentional intrathecal tranexamic acid injection, and cerebrospinal fluid lavage is promising. Developing a formalized protocol for intrathecal administration of local anesthetic solutions is advisable to avoid errors associated with accidental drug administration not intended for spinal anesthesia.