Of course I have a citation
Elson Haas, MD in his book "Staying Healthy with Nutrition" - which is an excellent book BTW for those interested in nutrition - writes:
Some recent reports in the medical literature show that regular usage of over 2,000 mg. per day, which some women especially have been taking, are correlated with episodes of peripheral neuritis. Although the experience of weakness or tingling of arms or legs has been transient and mostly correctable by decreasing the B6 dosage, this does warrant some concern about excessive use of B6, especially long-term use. Since part of the neuropathy problem comes from the liver's inability to convert all of the pyridoxine to active P5P, this concern can be lessened by supplementing some of the B6 as pyridoxal-5-phosphate (as I have done in many of my programs), especially when the dose of vitamin B6 exceeds 200 mg. per day."
So, yes, while B6 is water soluble and toxicity is rare in full grown adults, they do happen - and even less is known about how much would be toxic to a fetus, especially during such a crucial stage in their brain development.
I am certainly not saying that you should not take B6 for MS. Just the opposite, as it can be a very effective treatment. However, in general it is safest to take the minimum amount you need to feel better, rather than the maximum amount.
There have also been studies that show that ginger is just as effective as B6 for MS - without any possible toxicity. Such as this one:http://www.ncbi.nlm.nih.gov/entrez/q..._uids=14649969