Caffeine is a stimulant that is present in many substances such as coffee, tea, cola flavored beverages and chocolate. Caffeine is considered a drug because it works to stimulate the central nervous system. Caffeine is considered to be the most commonly used psychoactive drug in the world. It is estimated that 80 percent of the world uses caffeine on a daily basis.MedlinePlus: Caffeine

While moderate caffeine intake is considered to be relatively harmless, there are some potential side effects that can occur when it is consumed excessively. These can include lack of sleep, anxiety, irritability, upset stomach, rapid heart rate and headaches.http://www.mayoclinic.com/health/caffeine/NU00600

Caffeine is used to increase alertness and for a temporary energy boost. Caffeine can also affect mood. There is no health requirement for caffeine in a persons diet.IFIC: Everything You Need to Know About Caffeine

Some medications use caffeine as a catalyst to help the drug take effect. Pain relievers, for example, can work up to 40 percent more effectively when caffeine is added.http://www.webmd.com/migraines-headaches/guide/triggers-caffeine

Consuming excessive amounts of caffeine can lead to an overdose. Adults who have overdosed may experience problems breathing, vomiting, diarrhea, convulsions, general confusion and fever. Babies may tense up muscles, and then relax them. They may also throw up and have tremors.http://www.nlm.nih.gov/medlineplus/ency/article/002579.htm

Generally caffeine is considered safe in moderation. Researchers consider 200 - 300 mg of caffeine a day to be a moderate amount for adults. 100 mg a day can lead to a dependence on caffeine which can lead to withdrawal symptoms if you do without it.MayoClinic.com: Caffeine: How much is too much?

• Coca-Cola - 12 oz - 34 mg
• Diet Coke - 12 oz - 45 mg
• Iced tea - 12 oz - 70 mg
• Brewed coffee - 5 oz 115 mg
• Mountain Dew - 12 oz 55 mg
• Red Bull - 8.3 oz 80 mg
• Monster - 8 oz 116 mg
• Pepsi - 12 oz 38 mg
• Dark chocolate - 1 oz - 20 mg
• Milk chocolate - 1 oz - 6 mg

The content on this page is not a substitute for professional medical advice. Please contact your doctor or pharmacist before using the information presented here.