Mastic is a natural resin extracted from the stem of the evergreen tree Pistacia lentiscus var. Chia (Duham) (Anacardiaceae). For a long time, mastic has been esteemed for its aphrodisiac properties. To test this hypothesis, the trace element zinc was determined while the quantity released after a certain time of chewing was studied. For comparison, three commercial chewing-gums were analyzed as well. A portion of natural mastic or commercial gum was uniformly chewed for 1, 2, 3, and 4 h and the zinc content measured. The zinc content of mastic from P. lentiscus var. Chia was compared to that of other natural resins from the same genus (Pistacia terebinthus L.) or conifer [Pinus halepensis Mill. (Pinaceae)], having a different secretion mechanism and also used as an additive in human nutrition. Secreted resin and plant tissues from the above trees were sampled and the zinc content was determined. Zinc concentrations in the resin were lower than in the plant tissues. The Chios mastic showed a slightly greater zinc content compared to the other analyzed specimens. Among all gums studied, only the Chios mastic released a small amount of about 0.7 mg kg(-1) zinc in the mouth and gastrointestinal system after 4 h chewing time. With commercial gums, the zinc content increased to a large degree (up to 2 mg kg(-1)) after the same treatment, a fact which was attributed to the zinc uptake from salivary secretions, indicating zinc deprivation for the human organism.