Can ingestion of B6 cause gastrointestinal disturbance?

Question

Can the ingestion of vitamin B6 upset the stomach, and if so by what mechanism?

Answer 1

I have not found any specific reference that it does.

However, it is almost taken as a given that any drug can cause nausea, diarrhea, or headache. Most such reasons are considered idiosyncratic (particular to that person).

Unless it is very common or very severe they seldom look for a mechanism, as the usual course of action is just stopping the drug and trying another one.