What do systematic reviews say?

Folic or folinic acid (any) vs placebo

Folic or folinic acid (any) showed no clear difference in haematological disorders (neutropenia, etc) compared with placebo (low certainty).

• Folic acid and folinic acid for reducing side effects in patients receiving methotrexate for rheumatoid arthritis 2013 · Cochrane Headline outcomes only
  RR 1.55 [0.4, 5.91]
  2 studies · 443 participants
  Low