text: at what point can a person overdose on vitamin b6 and what are the effects of an overdose? i have cancer and the chemotherapy i'm on causes neuropathy. my oncologist has advised me to take 100mg ofvitamin b6, but this is not alleviating the symptoms. high doses of vitamin b6 (300 milligrams or more per day) for long periods of time (greater than 6 months) in a few people has caused peripheral neuropathy.  100 mg/day is considered safe.  i do not know why your doctor is recommending b6 for the treatment of your chemotherapy induced peripheral neuropathy.  i just did a 'quick' search of pubmed (where the world's medical research can be reviewed) and found several studies showing the supplement acetyl-l-carnitine may be effective for the treatment of chemotherapy induced peripheral neuropathies.  this might be a better 'bet' than b6.  you can read these studies by going to pubmed (enter 'entrez pubmed' in your search engine).  in the search window of pubmed enter: 'chemotherapy peripheral neuropathy acetyl-l-carnitine'.  you may want to share these studies with your doctor.  best wishes and good luck.