Teeth are in close contact with foodstuffs: phenomena such as caries and wear of the crowns are precious keys to gather information on diet and cooking techniques. Phytoliths are granules of hydrated amorphous silica, which are deposited in the oral cavity while chewing fruit and vegetables and incorporated into dental calculus during its formation. In diet investigation, different plants may therefore be related to specific phytolith shapes. Analysis of chemical trace elements, incorporated in dental calculus from ingested food and replacing small percentages of calcium in normal processes of resorption and redeposition, can further enrich the research on ancient diet. The aim of our work was to set up an analytical protocol, focalised on phytoliths and the inorganic elemental composition of dental calculus, on samples coming from medieval skeletons excavated in Caravate (Varese, Italy). The inductively coupled plasma mass spectrometry analytical technique proved to be particularly suitable for such studies. The results suggested a diet based both on the consumption of carbohydrates (dicotyledons and monocotyledons such as the Poaceae, also known as Gramineae; and Coniferae) and on proteins, mostly derived from fish. Copyright © 2015 John Wiley & Sons, Ltd.