Coffee contains a drug called caffeine. Over-consumption of caffeine will lead to the following problems:
Firstly, it will lead to Caffeine Induced Anxiety Disorder. Secondly, we will suffer from insomnia, that is, we will not be able to sleep. We might stare at the stars all night. Thirdly, potassium levels will go down, which will lead to heart palpitations or irregular heartbeat. Fourthly, caffeine being acidic, it might damage the lining of our digestive tract and further worsen existing stomach ulcers. Fifthly, caffeine can act as a diuretic, leading to excess urine production and thus dehydration. Also, caffeine has great laxative properties, but too much consumption can also lead to diarrhea. Lastly, over-consumption of caffeine may lead to development of chronic liver diseases.