Objective: The aim of this paper is to describe the chemical properties and toxicological effect of caffeine through a review of the literature with reference to its forensic significance. The aim of the experimental part of the paper is to determine the concentration of caffeine in 19 selected samples of teas, refreshing soft and energy drinks available on the Croatian market by UV-VIS spectrometry. Also, it is necessary to examine whether the obtained concentrations of caffeine comply with the legally prescribed maximum caffeine content in a particular type of beverage. Methods: Using standard solutions of caffeine of known concentrations and their absorbances measured by UV-VIS spectrometer at a wavelength of 274 nm, a calibration diagram was constructed and its equation was determined. The tea samples were infused in distilled water, after which the mixture was filtered and the filtrate mixed with chloroform in a separatory funnel. Samples of refreshing soft and energy drinks were degassed by heating to boiling and then extracted with chloroform in a separatory funnel. The extract thus obtained was diluted and its absorbance was measured by UV-VIS spectrometer at a wavelength of 274 nm. Caffeine concentrations in the samples were calculated using the calibration equation and the extract dilution factor. Results: The results of this research are consistent with similar research conducted so far. Samples of black teas contain higher concentrations of caffeine compared to green ones, while teas collectively have higher specific concentrations than other beverages analyzed. Energy drinks contain a higher concentration of caffeine compared to refreshing soft drinks in which the dietary versions of certain beverages have a lower concentration of caffeine than their original variants. Two samples of energy drinks showed a higher concentration of caffeine than the recommended one. Other samples contain concentrations of caffeine within the limits allowed by law, and all prescribed informations are stated on product declarations. Conclusion: Since caffeine is the most commonly consumed psychoactive substance, its toxicological impact on the human body has been well investigated. The forensic significance of caffeine is small, but there is a need to increase awareness of the negative impact and possible misuse of pure caffeine which is easily available on the market. The method of determining the concentration by UV-VIS spectrometry is extremely simple, fast, cheap and reliable. However, the extraction process did not show good repeatability, which is why it should be further adjusted through future research by reducing the number of steps in the protocol and the possible influence of the human factor on the results.