The "high" is caused by dextromethorphan, a common ingredient found in many cough medicines.
Dextromethorphan is a safe and effective ingredient when taken in the correct doses.
Dextromethorphan, the primary ingredient in many over-the-counter cough remedies, also depresses the brain's cough center but without the side effects associated with narcotics.
The most popular drug in this class is dextromethorphan, which is quite safe and is available without prescription.
The letters DM in a product's name normally indicates the presence of dextromethorphan, but it is always best to read the ingredients.