MDMA users typically pre-load with serotonin agonists (drugs that increase serotonin levels), such as 5htp (Allott & Redman, 2006). This reduces the negative short term effects of the drug as well as aiding in recovery time and improving comedown symptoms like depression. Cannabis has also been shown to reduce the negative side effects of MDMA and it has even been shown to protect rats from MDMA overdoses. If you want to protect yourself from long-term MDMA damage take 5htp pre and post-loadings and a low dose of smoked or eaten cannabis.
Allott, K., & Redman, J. (2006). Patterns of use and harm reduction practices of ecstasy users in Australia. Drug and alcohol dependence, 82(2), 168-176.
Jerome I. "Is THC Neuroprotective Against MDMA Toxicity?". Erowid Extracts. Nov 2010;19:7-9. Online edition: Erowid.org/chemicals/mdma/mdma_article5.shtm