The release of fluoride from a fluoride-containing bone meal tablet and a chewable sodium fluoride lozenge to 0.5 M perchloric acid, deionized water, and saliva was compared. In acid, all the fluoride was released from the bone meal tablet (0.25 mg F), while there was a poor release in water and saliva (2-10 %). The release from the sodium fluoride lozenge (0.25 mg F) was essentially complete in water and saliva as well as in acid. Following sucking and chewing on a sodium fluoride lozenge, the mean salivary fluoride concentration increased from 0.04 to 36 parts/10(6) 5 min after intake. Concentrations exceeding the preintake level were still recorded after 20 min. With the bone meal tablet, only a slight increase (to 0.2 parts/10(6)) in the salivary fluoride level was obtained.