This information is for people who have multiple sclerosis. It tells you about methotrexate, a treatment used to reduce relapses and disability in multiple sclerosis. It is based on the best and most up-to-date research.
Does it work?
We're not sure. If you have primary progressive or secondary progressive multiple sclerosis (MS), taking methotrexate tablets may slow down how quickly you become disabled. (For details, see Types of multiple sclerosis.) But there isn't enough research to be sure.
In the UK, methotrexate is not on the list of drugs that doctors are advised to use in MS. 
What is it?
Methotrexate is a drug that calms your immune system. You take it as a tablet once a week. The brand name is Maxtrex.
How can it help?
Taking methotrexate tablets may reduce your disability if you have primary progressive or secondary progressive MS. (With secondary progressive MS, some of your symptoms stay after a relapse and get worse over time. With primary progressive MS, your symptoms never really go away from the start. They slowly get worse but may vary over time.)
In one study: 
With no treatment, 8 in 10 people with progressive MS became more disabled over two to three years
But only 5 in 10 people taking methotrexate became more disabled.
However, this study only looked at 60 people. And when the researchers measured people's levels of disability, they looked mainly at how well people could move their arms. It's not clear whether the difference in disability that the study found was big enough to make people's lives easier.
How does it work?
No one knows exactly how methotrexate tablets work in MS. But the drug calms your immune system and reduces inflammation. This might help delay the nerve damage and disability caused by cells from the immune system attacking the coating of your nerves. (To learn more about what happens in MS, see What is multiple sclerosis?)
Can it be harmful?
There's a small risk that methotrexate will stop your bone marrow working properly or damage your liver. So you'll probably need to have regular tests if you take this drug to make sure it isn't harming you.
How good is the research on methotrexate?
The evidence that methotrexate helps people with multiple sclerosis (MS) is quite weak. We found one big summary of the research (known as a systematic review). This review found only one study of methotrexate.
This study included 60 people with progressive MS.  (For details on the different kinds of MS, see Types of multiple sclerosis.)
The study found that methotrexate tablets reduced disability more than a dummy treatment (a placebo). But most of the improvement was in how well people's arms worked. So we can't say how helpful these tablets are if MS affects other parts of your body.