Although the etiology of oral mucosal fibrosis (OSF) is complex, betel nut chewing is widely believed to be the primary cause. The alkaloids and tannins in betel nut are responsible for OSF. But the latest research suggests that copper ions may play an important role in OSF. The experiment was conducted by Gururaj and other scholars at Navodaya Dental Hospital in Hyderabad-Karnataka, India, and the findings were published in the latest issue of the British Journal of Oral and Maxillofacial Surgery. The researchers focused their investigation on the Hyderabad-Karnataka region of India, where people living in this region have a higher incidence of OSF than people in other regions. The researchers divided the population into the following three groups of one hundred people each. The first group had OSF and chewed gutkha tobacco (OSF group); the second group chewed gutkha tobacco but did not have OSF (non-OSF group); and the third group was a control group that did not chew gutkha tobacco and did not have OSF (control group). Serum and saliva specimens were collected from all three hundred subjects and were used to test for copper in the blood and plasma copper blue protein. All the investigated subjects were not allowed to chew betel nut one hour before obtaining saliva. The content of copper ions in drinking water was analyzed using flame atomic absorption spectrometry. The results showed that the mean copper concentration in drinking water measured using flame atomic absorption was significantly different between the two groups. In serum in saliva, copper ion content also showed differences between the groups. Plasma copper blue protein showed significant differences between the groups. The researchers concluded that copper ions in drinking water are involved in the pathological process of oral mucosal fibrosis, but the pathological process of OSF development is not due to a single factor of excessive copper intake.