Synthetic cannabinoids mimic the effects of cannabis and are the largest and fastest growing class of newly appearing designer drugs. Reports have revealed that various types of synthetic cannabinoids are mixed with herbal substances. The present study investigated the herbal substance cases involving synthetic cannabinoids in Ankara and nearby cities in Turkey. Data were collected from the reports of synthetic cannabinoids that were analyzed between January 01, 2011 and December 31, 2015 in the Ankara Narcotic Department of the Council of Forensic Medicine at the request of the judicial authorities. In all, 4610 narcotic reports were obtained and reviewed. Among these narcotic reports during the period, 370 reports (8%) were related to synthetic cannabinoids. 28 synthetic cannabinoid compounds could be identified in herbals: 5-F-AB-PINACA, 5-F-AKB-48, 5-F-NNEI, 5-F-PB-22, AB-CHMINACA, AB-FUBINACA, AB-PINACA, ADB-CHMINACA, ADB-FUBINACA, AKB-48, AM-2201, EAM-2201, JWH-018, JWH-022, JWH031, JWH-122, JWH-201, JWH-210, JWH-250, JWH-251, JWH-307, MAM-2201, NM-2201, PB-22, RCS-4, THJ-2201, UR-144, XLR-11. The amount of herbals was 30.72 g, 329.22 g, 665.89 g, 4844.7 g, and 5684.3 g in 2011, 2012, 2013, 2014, and 2015, respectively. Generally, herbals contained more than one synthetic cannabinoids. ADB-FUBINACA was the most common synthetic cannabinoid among the herbals determined in this study, which was 3132.43 g, excepting multi-synthetic cannabinoid herbals. The amount and diversity of synthetic cannabinoid compounds have increased dramatically between 2011 and 2015. (C) 2017 Elsevier B.V. All rights reserved.