Dextromethorphan, or DXM, is a cough suppressant that is an ingredient in over-the-counter (OTC) cold medications. When people take DXM in high doses, it can cause hallucinations and feelings of euphoria. However, overdosing on DXM can be dangerous. When people take the correct dosage of a cough medication, DXM does not pose a risk. However, some people misuse it in the hope of achieving a "high." In these cases, the side effects can be severe. Read on to learn more about DXM, its effects, and how to recognize when someone is misusing it. DXM is a drug in many OTC cold and cough medications. It is an antitussive — meaning a cough suppressor — that helps a person stop coughing by blocking the cough reflex in their brain. With correct use, experts consider medications that contain DXM to be safe . Many pharmacies and supermarkets sell medications containing DXM. These are available in many forms, including: tablets cough syrups capsules DXM is neither illegal nor a controlled s