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  • Barbiturates: act as central nervous system depressants and are used as sedatives or hypnotics. They may precipitate acute attacks.
  • Beta-carotene: a yellow pigment that gives color to plants such as carrots and tomatoes. It is often used as a treatment for sun-sensitive porphyria.
  • Bilirubin: formed as hemoglobin breaks down; gives bile its yellow green color.
  • Biochemical pathways: systems in the body for processing molecules for useful functions.
  • Biochemical tests:  tests based on the identification and measurement of porphyrins in samples such as, blood, urine and stool.
  • Biopsy, liver: requires a small core of liver tissue to be removed from the liver with a needle introduced between the lower ribs on the right side of the chest.
  • Bone marrow:  the tissue in the hollow inside of bones, responsible for making new blood cells.