I take warfarin how do tumeric, chilli, chia seeds, garlic, onions, ginger stinging nettle tea interact with warfarin?

Anticoagulation. Tumeric (Curcumin), Chia seeds, ginger extract, stinging nettles, garlic (Allium sativum), red onion extract (Allium cepa) and Capsicum (red pepper or chili pepper) can all interfere with coagulation of blood. Coumadin (warfarin) also effects coagulation. These can interact.
It's complicated but. I dislike warfarin because virtually every medicine and herb interacts with it. Turmeuric, chia seeds, garlic and ginger also thin blood and thus you might need to lower the dose. Rather than avoiding these one can consume consistent amounts & adjust coumadin accordingly or one can consider alternative meds or even supplements (under doc's guidance) to thin blood. Also see http://bit.ly/1hHlMAv .