Melatonin is a hormone produced by the pineal gland in your brain. The pineal actively converts serotonin to melatonin when it is dark, but when light is present it does not do so, and the melatonin oxidizes back into serotonin. Consult with your physician about taking melatonin. Taking melatonin pills is a natural way to induce sleep, especially if you are physically tired at night but are still unable to fall asleep. However keep in mind melatonin is a hormone (like estrogen or testosterone) and just because it is natural does not necessarily mean it is harmless. These are safe when taken "without extra ingredients"—–i.e. no pain relievers, decongestant, expectorant, etc., but only for a night or two, as tolerance to them quickly builds.  Read the labels. Try half or less of the usual dose so that you don’t end up with a "sleeping pill hangover," which will only make your sleep situation worse. Be lying down in bed when your drowsiness kicks in. If you use prescription drugs, check with your doctor before taking anything else. Never thoughtlessly mix medications: with the wrong combination, you could end up mixing medications in a way that will do you harm. Be sure not to abuse any sedative. Do not take those in more than the prescribed dosage, nor beyond the recommended duration. if you are concerned that you might have a sleep disorder. Some of the most common sleep disorders are insomnia, narcolepsy and parasomnias. If you are indeed suffering from and are diagnosed with any of these conditions, your doctor will recommend treatment accordingly. Anxiety, depression, PMS, and some medications can cause difficulty sleeping and should be addressed.

How would you rephrase that briefly using Vietnamese?
Thử dùng melatonin. Thử dùng thuốc kháng histamine gây buồn ngủ. Nói với bác sĩ