This study reviews the peripheral effects of methamphetamine on the salivary acini, the pathogenesis of methamphetamine-induced xerostomia, and its anecdotal relationship to dental caries. Methamphetamine is a sympathomimetic central stimulant which is abused for its euphoric effects. Its pharmacological action is exerted indirectly by sustaining high levels of catecholamines in the synaptic cleft and directly by binding to the postsynaptic adrenergic receptors. Methamphetamine abusers report subjective perception of xerostomia, which cannot be explained by the direct peripheral action of methamphetamine on the secretory acini. The drug may cause a decrease in salivary flow rate by centrally inhibiting salivatory nuclei via stimulation of alpha-2 receptors in the brain. Drug mediated dehydration state may influence the perception of dry mouth in abusers. The decreased salivary flow rate, either due to a central inhibitory action of methamphetamine or generalised dehydration, likely contributes to the increased occurrence of dental caries. Five cases of methamphetamine abuse are presented, three of whom experienced rampant dental caries. A direct association between methamphetamine abuse and the occurrence of rampant caries was not clear.