I drink herbal teas and I EBF. But I normally stick to "name brands" like Celestial Seasonings and only the flavor teas (Sleepytime and Honey Vanilla Chamomile are my favorties!). I stay away from teas that say they are for wellbeing, detox, energy, etc.
I am just getting over a cold and wanted tea while I was sick so I grabbed some mother's milk tea. I don't have supply issues normally but I figured with being sick I might want the boost. The box recommends 3 to 5 cups a day to help boost supply. If you don't need to increase your supply, 1 cup every so often or even once a day would probably only increase your supply marginally if at all.
Re: Herbal Teas while Breastfeeding