Question: why is folic acid important when taking methotrexate?
Answer: Taking folic acid Folic acid helps protect the healthy cells in your body and reduces some of the side effects of methotrexate. It can make you less likely to be sick (vomit) or get diarrhoea. Your doctor will usually start you on one 5mg folic acid tablet, taken once a week. Take it the day after your methotrexate.