Caffeine is probably the most frequently ingested pharmacologically active substance in the world.300 mg caffeine per day (equivalent to 4.6 mg kg-1 bw day-1 for a 65-kg person) while children should consume ?Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day-1 (equivalent to 6 mg kg-1 body weight day-1 in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility.2.5 mg kg-1 bw day-1.