The concentrations of putrescine, cadaverine, indole and skatole were determined in the saliva of healthy human volunteers upon waking and at time points during the day. Putrescine was found to be the most abundant of the amines studied, followed by cadaverine then indole. Skatole could not be detected in the saliva samples at any time point. The amines were found in the highest concentrations immediately upon waking (mean concentrations (microg/ml): putrescine 33.0+/-19.0, cadaverine 17.6+/-16.7 and indole 0.4+/-0.4) with a rapid decrease following consumption of breakfast and brushing their teeth (mean concentrations (microg/ml): putrescine 7.0+/-6.4, cadaverine 3.1+/-4.7 and indole 0.04+/-0.09). Putrescine and cadaverine then increased in concentration during the day apart from a decrease post-lunch caused by increased salivary flow and mechanical cleaning due to mastication. An analytical method based on high performance liquid chromatography and fluorescence detection has been developed to quantify amines in human saliva. Sodium fluoride has been shown to be an effective inhibitor of amine formation in saliva at room temperature allowing samples to be collected and kept without requiring cold storage.