My dad is on warfarin, my doc told him to avoid chamomile tea and cayenne pepper? why?

Liver metabolism: look on the internet for foods etc which interfere with the breakdown of Coumadin (warfarin) there are a lot of foods etc which change how it is broken down so levels are either too high or to low so it is important to always have your blood checks to make sure you are in the right range also there are new medications out which help the same but without blood tests so ask your provide

Drug interactions: There are many, many foods, supplements and meds that will interact with warfarin and decrease or increase its effect, resulting in excessive clotting or bleeding. This can be life-threatening. Follow your doctor's advice carefully, and always ask about potential interaction with warfarin anytime you consider a new medication or supplement or diet.

Coumadin(Warfarin): Best to avoid all supplements unless carefully researched metabolism and anticoagulant properties. The herb capsicum (cayenne) may prolong clotting time, Cayenne also inhibits liver enzymes (CYP1A2) and thus could slow the metabolism of warfarin. Coumarins in the herb chamomile might increase Coumadin's effect. A woman had internal bleeding post chamomile tea regularly +coumadin CMAJ Apr 15, 06