Caffeine is a natural substance commonly found in the beans, leaves, fruits and seeds of over sixty plants. Scientifically caffeine can be defined as a xanthine alkaloid compound that has the capacity to stimulate the nervous system of humans.

The use of caffeine in large amount and also over extended period of time results in what is termed as caffeinism, which combines physical addiction to caffeine and the resultant after effects.

The general harmful effects of caffeine include increased production of stomach acid, esophagitis, peptic ulcer, and gastroesophageal reflux disorders. Other symptoms of overuse of caffeine include persistent nervousness resulting in sleep disorders and weight loss, irritability, anxiety and hypertension, tremulousness, hyperreflexia or muscle twitching, insomnia and heart palpitations.

Use of caffeine in more quantities induces caffeine intoxication. Caffeine intoxication is associated with a number of disorders in humans including nervousness, insomnia, flushing of the face, gastrointestinal problems, increased urination, irregular heart beat, and psychomotor agitation.