Administration of tetracycline to children or pregnant women is known to adversely affect the color of developing teeth. This case report suggests the possibility that discoloration from tetracycline may not be limited to tooth development in the child, but may also affect the adutl dentition. When give over long periods of time in adults , the tetracycline molecule is incorporated into the continuously forming secondary dentin. It is possible that chronic sun exposure of the incorporated tetracycline may cause the formation of areddish-purple oxidation product, resulting in discoloration of the permanent teeth.