I'm looking for interventions to help with nausea, constipation and stomach/ intestinal pain after taking iron supplements. They're very anemia (recently hospitalized for it) so they need to be on an iron supplement. Currently taking MegaFood Blood Builder which causes these side effects, seems it happens with any iron supplement. My guess is that any iron supplement causes increased available iron in the digestive tract which changes the intestinal flora/ microbiome makeup. So then the proceeding thought is to support with herbs to support HCL production/ digestion and herbs that can alter the microbiome (in a good way) along with nutritive herbs as a tea (nettles etc). Thoughts for possible interventions are triphala, probiotics, bitters (they can't do alcohol though), a different iron supplement like Floradix, or other herbs like licorice that can alter the microbiome. What are your thoughts/ pieces of advice around this?

I would try Floradix or Spatone liquid Iron and see if they cause GI issues. This is a very common problem with iron supplements. Certainly probiotics, Triphala or bitters are fine in general but I do not think they will directly address this issue. Another possibility is to consume more heme iron and take it with Vitamin C.