Previous studies have produced conflicting reports about the possible relationship between the chewing and smoking of tobacco and the incidence of caries. This study identifies the total sugar and the fluoride concentrations of various forms of tobacco from different areas of the United States. This is the first part of an investigation of caries-promoting and caries-inhibiting substances in commercial tobacco products. The total sugar content of pouch and plug forms of tobacco was, on the average, highest, followed by decreasing concentration in the pipe, cigarette, cigar, and snuff forms of tobacco. Fluoride content of the plug and pouch forms of tobacco was highest, followed by cigar, snuff, pipe, and cigarette tobacco, respectively. Generally, nonsmoking forms of tobacco are most directly related to the potential promotion of caries. The total sugar content in the control tobacco leaves was comparable to that in cigars and snuff which have the least amount of sugar, whereas the fluoride content was similar to plug and pouch which have the highest amount of fluoride. Brands of snuff on average had the lowest concentrations of sugar (average 1.9%) and were among the products with the lowest fluoride content (average 0.26 ppm). Pouch and plug exceeded other forms in both sugar and fluoride content. Large variations in sugar and fluoride levels of tobacco products can exist form-to-form, store-to-store, brand-to-brand, and state-to-state. This may explain the diverse opinions of dental practitioners and investigators relative to the concept that tobacco increases or decreases dental caries.