The correct term for dental cavities is caries, caries odor may be caries-causing bacteria odor, embedded in caries food corruption or pulp necrosis, etc., as follows. 1. Caries-causing bacteria produce odor: Streptococcus, Lactobacillus, Actinomyces is the main caries-causing bacteria, caries-causing bacteria in the caries process of decomposition of organic matter to produce a large number of hydrogen sulfide substances, resulting in caries cavities odor. 2. Food corruption: larger caries cavities are easy to embed food, the residual food in the caries cavity fermentation and corruption, will emit a foul odor. 3. Pulp necrosis: After the necrotic pulp tissue is decomposed by decay bacteria, hydrogen sulfide will be produced, resulting in foul smell. There may be other reasons for the odor of caries, it is recommended to go to the hospital in a timely manner, to clarify the cause of the disease and then targeted treatment.