Background Mushroom poisoning can cause gastrointestinal, renal, and hepatic symptoms and even death. This descriptive study examined the demographic, clinical, and laboratory findings of patients with fungal poisoning, a type of fungus causing the poisoning, and the incidence and mortality rates of fungal poisoning in Kermanshah province, western Iran, from 2014 to 2018. Methods The medical records of 193 patients with mushroom poisoning from 2014 to 2018 were evaluated. The liver and kidney function tests, electrolytes, abdominal and pelvic ultrasound, chest x-ray, coagulation tests, and coagulation factors (fibrinogen, prothrombin) were assessed. Data were collected from the medical records of patients admitted to the Poisoning Center of Imam Khomeini Hospital in Kermanshah, Iran using a researcher-made checklist. Data were analyzed by SPSS (version 16) using descriptive statistics, including mean, standard deviation, and frequency distribution tables. Trend analysis for proportion was done by chi-square statistics in STATA-14 software (ptrend command). Results Of cases, ‌51.3% were male, 92.6% were city dwellers, 38.3% were aged 21–40 years, and 92.5% were poisoned during the spring. The fungus that caused poisoning was Amanita virosa. The gastrointestinal, nervous, and visual systems were the most common systems involved. The most common gastrointestinal symptoms included nausea and vomiting (72.0%) and abdominal pain (71.0%). Vertigo (11.9%) and headache (9.3%) were the most common neurological symptoms. The most common visual manifestation was blurred vision (7.8%). Of cases, 23.7% had metabolic acidosis. The increased alkaline phosphatase level was the most common liver disorder in 98.7% of the cases. Increased blood urea nitrogen and creatinine levels were also reported in 21.0% and 17.7% of the cases, respectively. The serum lactic dehydrogenase and creatine phosphokinase levels also increased in 99.3% and 30.2% of the patients, respectively. The mortality rate was 1.6% (n = 3). Conclusion The fungal poisoning diagnosis should always be considered in young patients referred to the emergency department with gastrointestinal complaints, a history of consuming wild self-picked mushrooms, and high liver and kidney test values. Since most fungal poisonings occur in the spring, it is necessary to inform the community of the dangers of consuming self-picked wild mushrooms, especially in this season.