Various clinical manifestations are observed in humans with altered metabolim, which are also manifested in oral cavity. Many of the disorders are manifested mainly in the tongue causing various appearances such as macroglossia as seen in acromegaly, hypothyroidism, hyperpituitarism, mucopolysaccharidoses, abnormal melanin pigmentation as seen in Addison's disease, decreased two point discrimination as reported in a case of Cushings syndrome, sore tongue and changes in taste perception are reported in diabetes mellitus.In some other metabolic disturbances, only a part of the tongue is affected, such as enlargement of fungiform papillae as seen in vitamin B1 deficiency or a part of tongue is involved first later involving entire tongue such as in vitamin B2 deficiency. Entire tongue shows glossitic changes as seen in vitamin B6, vitamin B12 deficiency.These diseases are manifested in various forms systemically and also manifests intraorally. Some diseases are manifested only intraorally and Dentists may be the first person to recognize the underlying disorder. Oral Diagnosticians have the responsibility of treating to some extent and further referral for adequate management.