Non-invasive test for assessing bacterial overgrowth of the small intestine

A method of assessing bacterial overgrowth in the small intestine of a subject comprising the steps of:

• a. administering an amount of carbon-labeled sorbitol or sorbitol derivative to said subject, wherein said sorbitol derivative has the characteristics of not being readily absorbed by said subject and being metabolizable by bacteria;
• b. collecting a specimnen from said subject;
• c. measuring an amount of labeled carbon in said specimen to obtain a measured amount;
• and
• d. comparing said measured amount with a positive standard and a negative standard to assess bacterial overgrowth in said subject,
• wherein said negative standard is an amount of expired labeled carbon in a control group without bacterial overgrowth, and wherein said positive standard is an amount of expired labeled carbon in a control group with bacterial overgrowth.