Last update Jan. 22, 2022

Carbon-14 labelled Urea


Safe substance and/or breastfeeding is the best option.

Carbon 14 (14C) is a radioactive isotope that is used to label urea and other substances for diagnostic purposes.

Since the last update we have not found any published data on its excretion in breast milk.

Urea is a natural component of the body and is also found in milk.(Wheeler RA 1991, Ross SA 1985)

The dose of urea from the breath test to rule out infection by Helicobacter pylori is 100 mg, an inconsequential amount since the endogenous production of urea is 25-35 g daily. (AEMPS 2004)

Although 14C is radioactive, a 14C breath test involves the same amount of radiation as the natural environment in one day, and all ingested radioactivity is excreted from the body within 72-120 hours. 14C-urea breath test is safe in pediatric patients. (Pathak 2010)
Breastfeeding does not need to be interrupted after performing a 14C Urea test on the mother. (Mattson 2015)

Breast-feeding is protective against Helicobacter pylori infection. (Chak 2009)

See below the information of these related products:

  • Carbon-13 labelled Urea (Safe substance and/or breastfeeding is the best option.)
  • Urea (Safe substance and/or breastfeeding is the best option.)


Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Carbon-14 labelled Urea is also known as

Carbon-14 labelled Urea in other languages or writings:


Carbon-14 labelled Urea belongs to this group or family:


Main tradenames from several countries containing Carbon-14 labelled Urea in its composition:


  1. ICRP 2015: Mattsson S, Johansson L, Leide Svegborn S, Liniecki J, Noßke D, Riklund KÅ, Stabin M, Taylor D, Bolch W, Carlsson S, Eckerman K, Giussani A, Söderberg L, Valind S; ICRP.. Radiation Dose to Patients from Radiopharmaceuticals: a Compendium of Current Information Related to Frequently Used Substances. ANNEX D. RECOMMENDATIONS ON BREAST-FEEDING INTERRUPTIONS. ICRP Publication 128. Ann. ICRP 44(2S). 2015. Table D1 p320-21. Abstract Full text (link to original source)
  2. Pathak CM, Kaur B, Khanduja KL. 14C-urea breath test is safe for pediatric patients. Nucl Med Commun. 2010 Sep;31(9):830-5. Abstract
  3. Chak E, Rutherford GW, Steinmaus C. The role of breast-feeding in the prevention of Helicobacter pylori infection: a systematic review. Clin Infect Dis. 2009 Feb 15;48(4):430-7. Abstract
  4. AEMPS. Urea C13. Ficha técnica. 2004 Full text (in our servers)
  5. Wheeler RA, Jackson AA, Griffiths DM. Urea production and recycling in neonates. J Pediatr Surg. 1991 Abstract
  6. Ross SA, Clark RM. Nitrogen distribution in human milk from 2 to 16 weeks postpartum. J Dairy Sci. 1985 Abstract

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