What to do about my friend who does mdma?

Reach out: Talk to your friend and urge him/her to seek treatment. Express your concerns honestly and clearly. You may also consider bringing your concerns to his/her family or other friends if your friend refuses to seek help. The impirtant thing to keep in mind is that your friend needs professional help and that sometimes being a friend means speaking hard truths with love. See samhsa.Gov for more info.