The aim of this project was to determine the severity of nursing caries, and to examine contributing behavioral factors, in a group of Vietnamese families in British Columbia, Canada. The data collected became the basis for a community-based oral health promotion program. Information on feeding, dental health practices, and dental caries were collected for 60 mother/child pairs. For children > or = 18 mos, prevalence of nursing caries was 64 percent. Sixty-five percent of all children had a naptime bottle, and 85 percent > or = 18 mos had a "comfort" bottle that was carried around, and drunk from during the day. Milk was the most common beverage. A "comfort" bottle was significantly related to the presence of nursing caries, P = 0.02; a naptime bottle had a less significant association, P = 0.07. Dental knowledge questions revealed that all mothers knew that a child who had a "comfort" bottle could get tooth decay, but 63 percent thought that cavities were not a problem in baby teeth.