Mushroom poisoning is a frequently encountered health problem around the globe. Depending on its type and toxin, it results in a wide spectrum of issues that range from asymptomatic findings to fatal organ failure. Since the toxin of the mushroom leading to poisoning is often unidentified, syndromic classification may benefit clinical management according to the findings of target organ system toxicity. A 64-year-old female patient with comorbidities such as diabetes mellitus, coronary artery disease, hypertension and hyperlipidemia was admitted to the intensive care unit. Approximately four hours after consuming wild mushrooms the patient’s diarrhea, muscle cramps, cold sweating, blurry vision, coughing and shortness of breath complaints have been begun. Her respiratory system examination revealed tachypnea, generalized bilateral rhonchus, bronchorrhea and wheezing. Patient was normotensive and had bradycardia (heart rate 35 beats/minute). She had anxiety and the Glasgow Coma score was 15. Her pupillary bilateral isochoric, miotic and light reflexes were diminished. In her arterial blood gas pH level 7.26, partial carbon dioxide pressure: 34 mmHg, potassium: 5.3 mmol/L, sodium: 130 mmol/L, lactate: 5.3 mmol/L, bicarbonate: 16 mEq/L and base excess: -10,3 mmol/L was found. Target organ system toxicity findings and timing of occurrence indicated early-onset cholinergic syndrome. Treatments that consisted of intravenous atropine, fluid, electrolytes and sodium bicarbonate alleviated the toxicity in a short period of time. Late mycologic examination results that followed the treatment revealed that the patient was poisoned by Inocybe lacera, a mushroom type that contains muscarine. With this case presentation, we summarized the syndromic classification that we use in the clinical management in the light of current information in the literature.