It isn't safe to consume alcohol when taking melatonin. Alcohol has been known to interfere with some medications and supplements, which include melatonin. It may strengthen or weaken the effects of melatonin. Combining them together may aggravate the sedative actions of both making it quite dangerous. A few of the safety concerns that arise when combining melatonin with alcohol are dizziness, trouble breathing, passing out, and the potential of falling. People may experience increased anxiety, a spike in heart rate, irritability, and the swelling of hands and feet. It would be safer to avoid alcohol when taking this supplement.