In Sudan, smokeless tobacco (ST)—locally known as toombak—was introduced approximately four centuries ago and remains widely used, particularly among males. Toombak is produced in a loose, moist form using the tobacco species Nicotiana rustica. The manufacturing process involves fermenting ground tobacco powder and mixing it with an aqueous solution of sodium bicarbonate, resulting in a highly addictive product with a strong aroma. The chemical composition of toombak is notable for its high alkalinity (pH 8–11), variable moisture content (6–60%), and substantial nicotine concentration (8–102 mg/g dry weight). It also contains exceptionally high levels of tobacco-specific nitrosamines, measured in micrograms (NNN: 420–1550; NNK: 620–7870; NAT: 20–290), making it one of the most potent carcinogenic ST products. Chronic toombak use leads to the development of clinically and histologically distinctive lesions at the site of application and is strongly associated with an increased risk of oral cancer, with a relative risk ranging from 7.3 to 73.0. Microbiome analyses of toombak users have revealed a predominance of the bacterial phyla Firmicutes and Actinobacteria, with Corynebacterium casei, Atopostipes suicloacalis, and Oceanobacillus chironomi identified as the most abundant species. Fungal analysis indicates a marked reduction in Candida species, with Aspergillus being the dominant genus. Additionally, toombak contains high concentrations of iron and volatile aldehydes, which contribute to its toxicity. Its non-homogeneous, abrasive texture, combined with high sodium content in its commercially available form, can lead to oral mucosal damage. Despite the well-documented association between toombak and oral cancer, as well as potentially malignant oral mucosal lesions, research on its effects on gingival and periodontal health remains limited.