Abstract Background The objective of the study was to assess the demographics, clinical parameters, and outcome of acute intoxications among adult patients admitted to a medical intensive care unit in southern Croatia. Materials and Methods An observational retrospective study was conducted over a 1-year period. The subjects were patients admitted to the intensive care unit for acute poisoning. Results In all, 81 subjects (32.1% females) aged 43.16 ± 14.77 years were admitted to the intensive care unit because of poisoning (14.97% of the total annual intensive care unit admissions). Psychiatric disorders were previously established in 76.5% participants, and 69.1% of all acute intoxications were classified as suicidal. Non-suicidal subjects differed from suicidal subjects in age (37.36 ± 9.71 vs. 45.75 ± 15.93 years; P = 0.009), in pCO2 (6.38 ± 1.78 vs. 5.50 ± 1.26 kPa; P = 0.020), in length-of-stay in intensive care unit (median 1.00, interquartile range 1.00 vs. median 2.00, interquartile range 2.00 days; P = 0.022), and in length-of-stay in hospital (median 2.00, interquartile range 2.00 vs. median 10.50, interquartile range 15.25 days; P < 0.001). Three (3.7%) patients died. Pharmaceutical psychoactive drug intoxications were the most common poisoning cases; of these, diazepam was the most frequent (16.8%), followed by ethanol (9.0%) and alprazolam (7.8%). Benzodiazepines/hypnotics were the most common group (28.7%), followed by antipsychotics (13.2%). Intoxications with more than 1 poison accounted for the largest number of cases (67.9%). The number of toxins was significantly correlated with length-of-stay in the hospital (rho = −0.265; P = 0.008), systolic blood pressure (rho = −0.318; P = 0.002), and diastolic blood pressure (rho = −0.262; P = 0.009). The electrocardiogram was considered abnormal in 50.62% of the cases. Conclusion Acute intoxicants were most commonly caused by psychiatric pharmaceutical drugs. Multidrug exposure was a typical pattern of acute intoxication.