Submucous fibrosis (SMF) an important precancerous condition occurs almost exclusively in Indians but cases have been reported from several countries throughout the world. The causes of SMF are unknown and there is no known treatment for it. Chillies, tobacco use, vitamin deficiencies and betel quid chewing have been implicated. Ramanathan is of the view that SMF seems to be the Asian version of sideropenic dysphagia. He suggests that SMF appears to be an altered oral mucosa following a prolonged period of chronic deficiency of iron and/or vitamin B complex especially folic acid. This changed state of the oral mucosa subsequently appears to develop more easily a hypersensz"tivity to oral irritants such as spices especially chillies and to the betel quid. He provides biochemical data as well as quotes several studies to support his hypothesis.