Purpose: The objective of this study was to develop a new scoring tool that is comprehensively applicable and predicts fatality within 24 h of intoxication. Methods: This was a cohort study conducted in two emergency medical centers from 2011 to 2012. We identified factors associated with severe/fatality. Through a discriminant analysis, we devised the aBIG (age, Base deficit, Infection, and Glasgow coma scale) score. To compare the ability of aBIG to predict intoxication severity with that of previous scoring systems such as APACHE II, MODS, SAPS IIe, and SOFA, we determined the receiver operating characteristic curves of each variable in predicting severe-to-fatal toxicity. Results: Compared with the mild/moderate toxicity group (n=211), the severe/fatal group (n=143) had higher incidences of metabolic acidosis, infection, serious mental change, QTc prolongation and hepato-renal failure. Age, base deficit, infection-WBC count, and Glasgow Coma Scale were independently associated with severe/fatal poisoning. These variables were combined into the poisoning "aBIG" score [$0.28{ imes}$Age group+$0.38{ imes}WBC$ count/$10^3+0.52{ imes}$Base deficit+$0.64{ imes}$(15-GCS)], which were each calculated to have an area under the curve of 0.904 (95% confidence interval: 0.868-0.933). The aBIG poisoning score had an equivalent level of severity predictability as APACHE II and a superior than MODS, SOFA, and SAPS IIe. Conclusion: We developed a simplified scoring system using the four variables of age, base deficit, infected leukocytosis, and GCS. The poisoning aBIG score was a simple method that could be performed rapidly on admission to evaluate severity of illness and predict fatal severity in patients with acute intoxications.