In 2011, Rickert et al. [Regul. Toxicol. Pharmacol. 2011 Nov;61(2):199-209] reported mutagenicity, cytotoxicity, and clastogenicity data for mainstream smoke (MSS) from cigarillos and similar products (sometimes called filtered cigars) that have dimensions similar to cigarettes. These products are often wrapped with a reconstituted tobacco wrapper without use of an underlying binder and have cellulose acetate filters similar to filters used on filtered cigarettes. The tobacco blends were suspected to be air-cured as is the case with most cigars, but the toxicity data reported by Rickert did not fully support that conclusion. Initial DS scan GC-MS analyses (SSPT 16, CORESTA Congress Edinburgh, 2010) revealed that products were fabricated from pipe tobacco, blended cigarette tobacco, or what appeared to be light air-cured tobacco blends that appeared to contain glycerine and sugars. However, the mainstream smoke from many of the filtered cigars had hedonic characteristics unlike larger cigars and unlike experimental cigarettes fabricated only with the grades of Burley tobacco used for US-blend cigarettes. Several Burley grades likely to be used in filtered cigars were obtained and routine tobacco analytes determined along with the detailed tobacco chemistries previously reported for filler from filtered cigars. Typical blend chemistries for the tobacco from filtered cigars were alkaloids, 1.3 to 1.5%; total sugars, 2.5 to 3.2%; reducing sugars, 2.5 to 3.2%; nitrate, 1.5 to 2.2%; and chloride, 1.5 to 1.9%. DS scan GC-MS data showed evidence for glycerine, fructose, glucose, caffeic acid (trace), sucrose, and chlorogenic acid. GC-MS data on Burley grades likely to be used for the blends used for the filtered cigars also showed evidence for the same set of compounds. Such blend chemistries may explain the toxicological findings as well as smoke sensory properties of these products.