Tea and coffee have been consumed for hundreds of years for their flavour and stimulating properties. Nowadays, caffeine is receiving an increasing interest in food and pharmaceutical industries due to its central nervous system CNS stimulating properties, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. Caffeine constitutes an average of 4% of tea leaf and 1.5% of coffee bean. The aim of this study is to assess the quality of commercial tea and coffee products based on caffeine levels by using high performance thin layer chromatography (HPTLC). The results showed the quality variation among the products examined of both tea and coffee. Additionally, one brand of tea was found to be completely adulterated. Conclusion: The used method is simple, rapid, reliable and suitable for evaluation of quality of caffeine containing preparations.

Keywords: Camellia sinensis, Coffea Arabica, Caffeine, High Performance Thin Layer Chromatography, Quality, Adulteration.