Caffeine is LIKELY SAFE for most adults when used appropriately. Caffeine is POSSIBLY UNSAFE when taken by mouth for a long time or in fairly high doses. Caffeine can cause insomnia, nervousness and restlessness, stomach irritation, nausea and vomiting, increased heart rate and respiration, and other side effects.
Consequently, how much caffeine is bad for you?
Up to 400 milligrams (mg) of caffeine a day appears to be safe for most healthy adults. That's roughly the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two "energy shot" drinks. Keep in mind that the actual caffeine content in beverages varies widely, especially among energy drinks.
What are the bad effects of coffee?
Coffee containing caffeine can cause insomnia, nervousness and restlessness, stomach upset, nausea and vomiting, increased heart and breathing rate, and other side effects. Consuming large amounts of coffee might also cause headache, anxiety, agitation, ringing in the ears, and irregular heartbeats.
What does caffeine do to the body?
Caffeine acts as a central nervous system stimulant. When it reaches your brain, the most noticeable effect is alertness. You'll feel more awake and less tired, so it's a common ingredient in medications to treat or manage drowsiness, headaches, and migraines. For example, too much caffeine can give you headaches.