The number of cigarette capsule users is increasing; however, a comprehensive epidemiological investigation comparing the harmfulness of capsule and non-capsule cigarettes, particularly concerning the composition of flavor components and mainstream smoke, is lacking. The present study aimed to investigate the effect of capsule burst on the compound composition of mainstream smoke by quantifying the Hoffmann list and flavor (geraniol, eugenol, menthofuran, and pulegone) in mainstream smoke with and without crushing the capsules. The findings indicate that while tar values tended to increase when the capsules were burst, there was no significant change observed in the other Hoffmann list components, such as nicotine, benzo[α]pyrene, tobacco-specific nitrosamines, aromatic amines, and phenolics. However, when the capsules burst, menthofuran and pulegone, which were present in the capsule and could cause toxicity, were found in the mainstream smoke via the International Standard Organization (1.5–4.0 μg/cig and 5.13–6.00 μg/cig smoking regime) and Health Canada Intense (12.8–18.2 μg/cig and 22.77–24.67 μg/cig smoking regime). Therefore, understanding the capsule composition is important, as the toxic components of the capsules can be inhaled as smoke, posing a potential health risk.