Honestly I was also quite unsure about this when I was breastfeeding, and a few of us in my mum group had the same question about herbal supplements. I would really suggest checking with your gynae or a TCM practitioner first, just to be safe, since things like ginseng and cordyceps can have stronger effects and it is better to get a professional opinion before taking them while nursing. One of my mum friends also called up KKH's lactation line to ask about supplements like this and found it really helpful. Better to double check than to worry later lah.