Any of many reasons can cause your teeth to get stained over a period of time. If you understand these, maybe you can delay the discoloring of your beautiful teeth. Most important among the modern causes are smoking and drinking, both non-essential activities. Excessive drinking of tea and coffee is also a reason. Hereditary tendencies also exist among some people which cause their teeth to pale. Prolonged use of some antibiotics has also been noted as a reason for teeth getting stained. A growing cause of teeth discoloration in developing countries is lack of good oral and general hygiene and gastric acidity due to various changes in lifestyle and food intake.