What are the effects of chamomile tea on lab tests?

* Blood clotting tests. Chamomile may prolong bleeding time and interfere with blood clotting tests, such as the prothrombin time (PT) and international normalized ratio (INR). This is because chamomile contains coumarin, a compound that has anticoagulant effects.

* Liver function tests. Chamomile may increase the levels of certain liver enzymes, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). This is because chamomile contains compounds that can damage the liver.

* Kidney function tests. Chamomile may decrease the levels of creatinine and urea nitrogen in the blood. This is because chamomile contains compounds that can increase urine output and flush out these substances from the body.

It is important to tell your doctor if you are taking chamomile tea or any other herbal supplements before you have any lab tests. This will help your doctor interpret the results of your tests and make sure that you are not getting any false positives or negatives.

In general, it is best to avoid drinking chamomile tea for at least 24 hours before having any lab tests. This will give your body time to clear out any of the compounds that could interfere with the tests.