Other sources include the leaves of yaupon holly, South American holly yerba mate, and Amazonian holly guayusa; and seeds from Amazonian maple guarana berries. Temperate climates around the world have produced unrelated caffeine-containing plants. Caffeine in plants acts as a natural pesticide: it can paralyze and kill predator insects feeding on the plant. High caffeine levels are found in coffee seedlings when they are developing foliage and lack mechanical protection. In addition, high caffeine levels are found in the surrounding soil of coffee seedlings, which inhibits seed germination of nearby coffee seedlings, thus giving seedlings with the highest caffeine levels fewer competitors for existing resources for survival. Caffeine is stored in tea leaves in two places. Firstly, in the cell vacuoles where it is complexed with polyphenols. This caffeine probably is released into the mouth parts of insects, to discourage herbivory. Secondly, around the vascular bundles, where it probably inhibits pathogenic fungi from entering and colonizing the vascular bundles. Caffeine in nectar may improve the reproductive success of the pollen producing plants by enhancing the reward memory of pollinators such as honey bees.The differing perceptions in the effects of ingesting beverages made from various plants containing caffeine could be explained by the fact that these beverages also contain varying mixtures of other methylxanthine alkaloids, including the cardiac stimulants theophylline and theobromine, and polyphenols that can form insoluble complexes with caffeine. Products
Products containing caffeine include coffee, tea, soft drinks ("colas"), energy drinks, other beverages, chocolate, caffeine tablets, other oral products, and inhalation products.
To be initiated under a guru, one must have had no caffeine, alcohol, nicotine or other drugs, for at least a year.Caffeinated beverages are widely consumed by Muslims today. In the 16th century, some Muslim authorities made unsuccessful attempts to ban them as forbidden "intoxicating beverages" under Islamic dietary laws. Other organisms
Recently discovered bacteria Pseudomonas putida CBB5 can live on pure caffeine and can cleave caffeine into carbon dioxide and ammonia.Caffeine is toxic to birds and to dogs and cats, and has a pronounced adverse effect on mollusks, various insects, and spiders. This is at least partly due to a poor ability to metabolize the compound, causing higher levels for a given dose per unit weight. Caffeine has also been found to enhance the reward memory of honey bees. Research
Caffeine has been used to double chromosomes in haploid wheat. See also
Theobromine
Theophylline
Methylliberine
Adderall
Amphetamine
Cocaine
Nootropic
Wakefulness-promoting agent

References
Notes
Citations

Bibliography
Bersten I (1999). Coffee, Sex & Health: A history of anti-coffee crusaders and sexual hysteria. Sydney: Helian Books. ISBN 978-0-9577581-0-0. Carpenter M (2015). Caffeinated: How Our Daily Habit Helps, Hurts, and Hooks Us. Plume. ISBN 978-0142181805. Pendergrast M (2001) [1999]. Uncommon Grounds: The History of Coffee and How It Transformed Our World. London: Texere. ISBN 978-1-58799-088-5. Pollan M (2021). This Is Your Mind on Plants. Penguin Press. ISBN 9780593296905. External links

GMD MS Spectrum
Caffeine: ChemSub Online
Caffeine at The Periodic Table of Videos (University of Nottingham)