Caffeine is a very common substance that is contained in chocolate, soft drinks, tea, coffee, and can also be purchased as capsules, tablets, or powder. The chart below shows dosages for common caffeine products measured in milligrams (mg).

For caffeine levels in common foods and beverages, see the Caffeine Content of Beverages, Foods, & Medications.

Please Note: Caffeine in concentrated forms such as pills or powders can accidentally be taken in sufficient quantities to cause vomiting, unconsciousness, and death. A single box of Vivarin or No-Doze (US Products) can be fatal if taken at one time. Although possible with coffee or other strongly caffeinated drink, it generally requires much more awareness of the large dosage before dangerous levels are reached.

Oral Caffeine Dosages Threshold 10 - 20 mg Common 50 - 150 mg Strong 150 - 400 mg Heavy 400 + mg Lethal 3-20 grams oral (estimated, see below) LD50 (Lethal Dose*) 192 mg/kg in rats

Onset : 5 - 10 minutes Duration : 1.5 - 5 hours Normal After Effects : up to 24 hours

* LD50 = dose which will kill 50% of the tested animals. It is estimated that fatal doses for humans are between 3 and 20 grams of caffeine taken orally, depending on body weight and tolerance.

See Caffeine Overdose for more information about case reports of caffeine fatalities.