This study aimed to investigate the association of characteristics and clinical outcomes of patients who presented with mushroom intoxication. We conducted a retrospective study of mushroom intoxication cases using national registry data (representative of the period 01 January 2011 to 31 December 2019). Specifically, we analyzed the demographics, vital signs, mental status, intoxication related factors, and clinical presentations of the patients. The outcomes were assessed based on general ward admission, intensive care unit (ICU) admission, length of hospitalization, and mortality. The t-test or chi-square test were used to compare the emergency department (ED) discharge group and admission group. Logistic regressions were used to predict patients that were high-risk with regards to being admitted. A total of 393 patients with mushroom intoxication were presented at the ED, and the highest number of visits occurred in the month of September. Overall, 277 (70.5%) patients were discharged from the ED and 116 (29.5%) patients were admitted. Of these, 25 (6.4%) patients were admitted to the ICU, and 3 (2.6%) patients died. Patients are more likely to be admitted to the general ward or ICU when symptoms presented after 6 h: 6 to 24 h (Odds ratio (OR) 2.158; 95% Confidence interval (CI), 1.218–3.816) or >24 h (OR: 3.382; 95% CI, 1.438–8.050). Additionally, when the patients presented with diarrhea, they were more likely to be discharged with favorable outcomes with a less likelihood for admission (OR: 0.237; 95% CI, 0.093–0.523). Most cases of mushroom intoxication presented with gastrointestinal symptoms and followed a benign course. The longer time to onset of symptoms increased the likelihood of hospitalization. Clinicians should evaluate more carefully, observe, or admit those with delayed symptom onset.