Purpose: Acetanilide has been in widespread use as an amide herbicide compound. However, available data regarding acute human poisoning is scarce. The aim of this study was to analyze the clinical characteristics of acetanilide poisoning in order to identify the risk factors associated with severity. Methods: We conducted a retrospective observational study encompassing the period January 2005 to December 2010, including adult ED patients suffering from acetanilide intoxication. Toxicological history, symptoms observed, clinical signs of toxicity, and laboratory test results were collected for each patient. The patients were classified into two groups for analysis, according their poisoning severity score (PSS). Resulting clinical data and prognostic variables were compared between mild-to-moderate poisoning (PSS 1/2 grades), and severe poisonings and fatalities (PSS 3/4 grades). Results: There were a total of 37 patients, including 26 alachlor, 6 s-metolachlor, 4 mefenacet, and 1 butachlor cases. The majority of patients (81.1%) were assigned PSS 1/2 grades. Changes in mental status and observation of adverse neurologic symptoms were more common in the PSS 3/4 group. The median ingested volume of amide herbicide compound was 250 ml (IQR 200-300 ml) in the PSS 3/4 group, and 80 ml (IQR 50-138 ml) in the PSS 1/2 group. Also, the median GCS observed in the PSS 3/4 group was 13 (IQR 10-14), which was markedly low as compared to a median GCS of 15 in the PSS 1/2 group. Overall mortality rate was 5.4%, and profound cardiogenic shock was observed prior to death in all fatalities. Conclusion: When compared to previous reports, acute acetanilide poisoning resulted in relatively moderate severity. The presence of neurologic manifestations, hypotension, lower GCS score, and larger ingested volumes was associated with more serious effects and mortalities.