Cannabis is one of the oldest known medicinal plants, and a large variety of biological activities have been described. The main constituents, the cannabinoids, are thought to be most important for these activities. Although smoking of cannabis is by far the most common way of consumption, a significant part of medicinal users consume it in the form of a tea. However, not much is known about the composition of cannabis tea, or the effect of different parameters during preparation, handling or storage. In this study we used the high-grade cannabis available in Dutch pharmacies to study the cannabinoid composition of tea under standardized and quantitative conditions. Experimental conditions were systematically varied in order to mimic the possible variations made by medicinal users. During analysis there was a specific focus on the cannabinoid tetrahydrocannabinol and its acidic precursor, tetrahydrocannabinolic acid. Also the role of non-psychoactive cannabinoids as components of cannabis tea are discussed. The results obtained in this study provide a clear quantitative insight in the phytochemistry of cannabis tea preparation and can contribute to a better appreciation of this mode of cannabis administration.