What colour is caffeine in its pure form?

Caffeine is a naturally occurring chemical stimulant. It is a drug, and actually shares a number of traits with more notorious drugs such as amphetamines, cocaine and heroin. In its pure form, caffeine is a white crystalline powder that tastes very bitter. It is medically useful to stimulate the heart and also serves as a mild diuretic, increasing urine production to flush fluid out of the body.

Caffeine has been an integral part of global culture for hundreds of years. African folklore sets the discovery of coffee's energizing properties around 800 A.D., European and Asian accounts indicate that coffee and tea were local staples as early as the 1400s. Although coffee was often seen as a rare luxury for societies far removed from coffee-growing regions, foods and drinks made from other caffeine-containing plants were likely part of humankind's medical and nutritional arsenal since before recorded history.

Caffeine is classified by the US Food and Drug Administration as generally recognized as safe. Toxic doses, over 10 grams (.3 oz) per day for an adult, are much higher than the typical dose of under 500 milligrams (.02 oz) per day. It requires roughly 50–100 ordinary cups of coffee to reach the toxic dose. However, pure powdered caffeine, which is available as a dietary supplement, can be lethal in tablespoon-sized amounts.