The U.S. Food and Drug Administration says 400 milligrams of caffeine a day is generally safe for most people. That’s about the amount of caffeine in four cups of brewed coffee, 10 cans of soda or two energy shot drinks. Doses of 500 milligrams or more can cause caffeine intoxication. Symptoms of caffeine intoxication can include: Anxiety
Bowel irritability
Elevated blood pressure
Increased gastric acid
Insomnia
Panic attacks
Fortunately, there are no long-lasting consequences to caffeine toxicity as the symptoms wear off as soon as the caffeine leaves the system. If you’re concerned about your blood pressure or mental health, try limiting your caffeine intake to 200 milligrams a day (or two cups of brewed coffee).