Doctors warn over dangers of high-caffeine gum | Nursing Times (https://www.nursingtimes.net/news/primary-care/doctors-warn-over- dangers-of-high-caffeine-gum-29-05-2009/) Worryingly, the 320mg taken over a 4 hour period which resulted in the 13 year old being hospitalised is less than the 400mg recommended safe dose quoted on high strength caffeine gum promoted and handed out to athletes, including U18s, at mass participation running events in Scotland and Wales.