Background: The article aimed to assess the activity of the hexosaminidase (HEX) and its HEX A and HEX B isoenzymes in persons who suddenly died due to ethanol poisoning and explain the cause of their death. Methods: The research involved two groups of the deceased group A—22 people (20 males, 2 females; the average age 46 years) who died due to alcohol intoxication (with the blood alcohol content of 4‰ and above in all biological materials at the time of death—blood, urine, cerebrospinal fluid, and vitreous humor), and group B—30 people (22 males, 8 females; the average age 54 years), who died suddenly due to other reasons than alcohol. Results: The highest activity of the HEX was found in the serum of A and B groups. A significantly lower activity of HEX, HEX A, and HEX B was observed in the urine of group A in comparison to the sober decedents. Conclusion: The lower activity of HEX and its isoenzymes in the dead’s urine due to ethanol poisoning may suggest its usefulness as a potential marker of harmful alcohol drinking. Damage done to the kidneys by ethanol poisoning may be one of the possible mechanisms leading to death. Kidneys may be damaged intravitally via the inflammatory agent. Thus, it is necessary to conduct further research to evaluate the diagnostic usefulness of exoglycosidases while determining the death mechanisms of people who lost their lives due to ethanol poisoning.