Purpose: We aimed to evaluate the effects of Bonsai, a synthetic cannabinoid, on patients’ respiratory parameters. Materials and Methods: We retrospectively reviewed the medical records of 52 patients who admitted emergency department (ED) of Samsun Training and Research Hospital between December 2013 and December 2014 after self-reported Bonsai use. We assessed the time from intake to admission, symptoms, physical examination findings, vital signs, arterial blood gas analysis and other laboratory tests at presentation. Results: The mean time to admission was 89.7±57.8 (Min.:30; Max.:250) minutes. The most common symptom was an altered mental state in 23 patients (44.2%), followed by agitation in 13 patients (25.0%), ataxia in 12 patients (23.0%), hallucinations in 8 patients (15.4%) and nausea and vomiting in 2 patients (3.8%). Bradipne was the common finding in all patients. Also, hypoxia and hypercapnia were detected in arterial blood gas analysis of all patients. In addition the alveolar-arterial oxygen gradient levels (A-a O2) were also elavated. The mean partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2) and A-a O2 gradient values were 67.6±29.8 mmHg, 50.4±8.6 mmHg and 19.4±26.6 mmHg, respectively. There was an inverse relationship between the time from intake to admission and parameters of blood gas analysis. (p=0,001) Conclusion: Clinicians should be aware of the importance of early blood gas analysis and respiratory depression in order to provide early oxygenation and respiratory support in patients admitted to the ED as a result of synthetic Cannabinoid/Bonsai use.