Yes, caffeine is naturally present in all teas. Every 8-oz cup of our black teas (including diet) has 15mg of caffeine. Every 8-oz cup of our green teas (including diet) has 7.5 mg of caffeine. AriZona green tea with ginseng and honey tastes more like a can of Coca-Cola than true green tea. Although it contains no actual cola ingredients, it does contain caffeine which leads some people to think it's okay to drink it every day like coffee or soda. The amount of caffeine in your tea depends on how it's made. The more processed the tea, the more caffeine there will be. Black tea tends to have more caffeine than green tea. Even though both black and green teas are derived from the same plant, different processing methods are used to make them taste different. Unoxidized tea leaves are fermented first before they're rolled into balls or strung up into bags. This process gives the tea its color and flavor. Oxidized tea is dried without being fermented. It usually comes in white bags because the pigment would disappear during drying. Tea is one of many products that contain caffeine. Coffee, cola, chocolate, and even some dairy products such as ice cream and milk contain caffeine too. Caffeine increases the effects of adrenaline by blocking certain enzymes called adenosine receptors inside cells. This makes you feel more alert and ready to take on the world. However, too much caffeine can cause anxiety, irritability, diarrhea, and headaches.