Cough syrup is often seen as a quick fix for cold and flu symptoms. It’s in every pharmacy, grocery store, and medicine cabinet, marketed as a safe way to suppress a cough so you can sleep better and get through the day. But what if the very thing you’re taking to feel better is actually harming your brain?
Most popular cough syrups contain an ingredient called dextromethorphan (DXM), a synthetic compound that doesn’t treat the root cause of a cough—it chemically alters brain function to stop you from coughing. Instead of soothing the throat, reducing inflammation, or fighting off an infection, DXM blocks signals in the brain that trigger the coughing reflex. This means you still have congestion, irritation, and inflammation, but your body can no longer respond to it properly.
What makes this even more concerning is that DXM is classified as a dissociative hallucinogen, similar to drugs like PCP and ketamine. While it doesn’t always produce intense hallucinogenic effects at standard doses, it still acts on the brain in a way that disrupts normal neurological function. This raises important questions about long-term safety, side effects, and the real impact of regularly using DXM-based cough syrups.
How Dextromethorphan Works and Why It’s a Problem
Dextromethorphan was developed in the 1950s as an alternative to codeine-based cough medicines. While it is not an opioid, it still affects the central nervous system, altering the way the brain processes signals.[1]
Here’s how it works:
- DXM binds to NMDA receptors in the brain, preventing them from properly transmitting signals that trigger the coughing reflex. This means you stop coughing, even if your body still needs to clear mucus and irritants from your airways.
- At higher doses, DXM acts as a dissociative drug, meaning it can cause cognitive impairment, altered perception, and even hallucinations.
- DXM also affects serotonin levels in the brain, which can lead to mood disturbances, anxiety, and even dangerous interactions with other medications that also affect serotonin.
While DXM may provide temporary relief from coughing, it comes at a cost. Shutting down a natural reflex doesn’t help the body heal—it simply masks symptoms while exposing the brain and body to unnecessary risks.
The Health Risks of Dextromethorphan
Despite being widely available and commonly used, DXM is far from harmless. It has been associated with a range of neurological, cardiovascular, gastrointestinal, and psychological effects, even at standard doses.[1]
- Neurological Effects
- Dizziness and disorientation, especially in people sensitive to neurological stimulants
- Confusion, memory impairment, and difficulty concentrating
- Seizures in individuals who are predisposed to neurological disorders
- Interference with neurotransmitters, which can contribute to long-term cognitive disturbances
- Cardiovascular Risks
- Increased heart rate (tachycardia), which can strain the heart
- Elevated blood pressure, which is dangerous for people with hypertension
- Risk of irregular heart rhythms, particularly when DXM is combined with other medications
- Gastrointestinal Issues
- Nausea, vomiting, and stomach cramps
- Loss of appetite due to DXM’s impact on serotonin levels
- Dehydration from excessive vomiting or diarrhea in sensitive individuals
- Psychological Effects
- Agitation, restlessness, and heightened anxiety
- Mood swings or sudden irritability
- Dissociation, where individuals feel detached from reality
- Hallucinations or paranoia at high doses
These side effects highlight why DXM is more than just a simple cough suppressant. It actively alters brain chemistry, cardiovascular function, and digestive health, often leading to more problems than solutions.
Why DXM Is Still in Over-the-Counter Medications
If DXM comes with so many risks, why is it still the go-to ingredient in mainstream cough syrups? The answer, as with many pharmaceutical ingredients, lies in industry convenience and profitability rather than true health benefits.
- It’s Cheap and Easy to Produce
- DXM is a synthetic compound that can be produced in large quantities at a low cost. Unlike natural remedies, which rely on real plant extracts or biologically supportive compounds, DXM is cheap, scalable, and profitable.
- It’s Not an Opioid, So It Avoids Extra Regulations
- Many countries have cracked down on codeine-based cough syrups due to their opioid content. Because DXM is not classified as an opioid, it has avoided strict regulations, allowing it to be freely sold without a prescription.
- Consumers Don’t Question Over-the-Counter Drugs
- Most people trust that if a product is available at a pharmacy, it must be safe. This mindset has allowed potentially harmful ingredients like DXM to remain in circulation for decades without major scrutiny.
DXM and the Risk of Abuse
Beyond its standard health risks, DXM has a history of abuse, particularly among teenagers and young adults. Because it is a dissociative drug, taking high doses can produce hallucinogenic and euphoric effects, leading to a phenomenon known as “robotripping” or “skittling.”[3]
Signs of DXM abuse include:
- Slurred speech and impaired coordination
- Unusual drowsiness or extreme excitability
- Nausea and vomiting, often followed by dehydration
- Visual or auditory hallucinations
- Paranoia or unusual mood swings
This is yet another reason to be cautious about keeping DXM-based cough syrups in the home, especially in households with teenagers or young adults. What is marketed as medicine can, in reality, have mind-altering effects that make it dangerous in both the short and long term.
Safer Alternatives to DXM-Based Cough Syrups
The good news is that you don’t need DXM to get through a cold. There are plenty of safer, more effective alternatives that actually support healing rather than simply suppressing symptoms.
- Raw Honey
- Studies have shown that raw honey is just as effective—if not more effective—than over-the-counter cough suppressants. It coats the throat, soothes irritation, and has natural antimicrobial properties to help fight infections.[4]
- Herbal Teas
- Teas made with ginger, marshmallow root, licorice root, or thyme can reduce cough frequency, soothe inflammation, and support immune function naturally.[5]
- Salt Water Gargles
- A simple gargle with warm salt water can help break up mucus, reduce throat irritation, and provide relief without the use of synthetic chemicals.[6]
- Steam and Essential Oils
- Inhaling steam with essential oils like eucalyptus or peppermint opens airways, relieves congestion, and helps clear out mucus naturally.[7]
- Hydration and Electrolytes
- Drinking plenty of water, bone broth, and herbal teas can keep the throat moist and reduce irritation, while also supporting immune function.
Final Thoughts
Dextromethorphan is one of the most widely used cough suppressants, but its risks far outweigh its benefits. Rather than helping the body heal, it chemically interferes with brain function, suppressing symptoms in a way that can have long-term consequences. Its classification as a dissociative drug, its ability to alter neurotransmitter function, and its association with cardiovascular stress all raise serious concerns about its widespread use.
For those who prioritize true health, avoiding DXM-based cough syrups is a simple but important step. Natural remedies that support the body’s ability to heal—rather than override its signals—are far safer and more effective in the long run. Whether it’s raw honey, herbal teas, salt gargles, or hydration, there are better ways to handle a cough than shutting down your brain’s natural response with a synthetic chemical.
Making informed choices about what goes into your body is critical, especially when it comes to medications that interfere with the nervous system. By choosing natural, science-backed alternatives, you can protect your health while giving your body the real support it needs to heal.
References:
- Journey, Jonathan D., et al. “Dextromethorphan Toxicity.” StatPearls, StatPearls Publishing, 2025.
- Schifano, Fabrizio, et al. “Focus on Over-the-Counter Drugs’ Misuse: A Systematic Review on Antihistamines, Cough Medicines, and Decongestants.” Frontiers in Psychiatry, vol. 12, May 2021, p. 657397.
- Abuelgasim, Hibatullah, et al. “Effectiveness of Honey for Symptomatic Relief in Upper Respiratory Tract Infections: A Systematic Review and Meta-Analysis.” BMJ Evidence-Based Medicine, vol. 26, no. 2, Apr. 2021, pp. 57–64.
- Bode, Ann M., and Zigang Dong. “The Amazing and Mighty Ginger.” Herbal Medicine: Biomolecular and Clinical Aspects, edited by Iris F. F. Benzie and Sissi Wachtel-Galor, 2nd ed., CRC Press/Taylor & Francis, 2011.
- Tiong, Vunjia, et al. “The Effectiveness of Various Gargle Formulations and Salt Water against SARS-CoV-2.” Scientific Reports, vol. 11, Oct. 2021, p. 20502.
- Köteles, Ferenc, et al. “Inhaled Peppermint, Rosemary and Eucalyptus Essential Oils Do Not Change Spirometry in Healthy Individuals.” Physiology & Behavior, vol. 194, Oct. 2018, pp. 319–23.