I met with my oncologist and cancer pharmacist and I had to quit all Vitamin C because there are blood thinners in Vitamin C, I could take my calcium and highly recommended Vitamin D.

I did not have chemo

My Dr said to continue taking the vitamins and supplements I was taking before Chemo but don't add anything.

My oncologist let me stay on the multi vitamin! I'm taking extra calcium and vitamin D now for my bones. He told me vitamins were fine. I guess each doctor is different and maybe it depends on the type of chemo you're doing. I just asked him about different over the counter meds or any others before taking.

My doc took me off the fish oil and glucosamine I was taking, she said they can both cause blood thinning. I would do what ever you doc wants. Different chemos, different pre-meds, etc can all be different than any of us has taken.