Mixing drugs from the same category increases the effects of that category. Mixing drugs from different categories puts a strain on your system by forcing it to do two different things. If you take a drug with stimulant effects (like MDMA) and one with depressant effects (like alcohol) together, you’re asking your heart to speed up and slow down at the same time. The effects don’t cancel each other out; they just put a strain on your poor heart!
Mixing MDMA and alcohol has the added risk of increasing dehydration, leading to heatstroke. If you do mix these two, make sure you drink sips of water regularly throughout the session. The extra dehydration will also make your comedown worse.
MDMA has both stimulant and hallucinogenic effects. Hallucinogens also speed the heart up. Mixing MDMA with other hallucinogens (like cannabis) speeds the heart up even more. This can lead to overdose – convulsions and heart attack