i've found a list with the dangers of DXM...
Maybe it was an allergic reaction?
Important Short-Term Dangers:
* Nausea, diarrhea, vomiting, and allergic reactions (often from the cough syrup itself)
* Hot flashes, dizziness, and bad trips
* Psychotic breaks (generally from high dose use)
* Poisoning from Bromide Ions (Bromism)
Important Long-Term Dangers:
* Psychological addiction and depression (from regular use)
* Poisoning from Bromide Ions.
* Irreversible brain damage (from chronic use at high doses)
http://www.drugs-forum.co.uk/forum/showthread.php?t=17894
Maybe it was an allergic reaction?
Important Short-Term Dangers:
* Nausea, diarrhea, vomiting, and allergic reactions (often from the cough syrup itself)
* Hot flashes, dizziness, and bad trips
* Psychotic breaks (generally from high dose use)
* Poisoning from Bromide Ions (Bromism)
Important Long-Term Dangers:
* Psychological addiction and depression (from regular use)
* Poisoning from Bromide Ions.
* Irreversible brain damage (from chronic use at high doses)
http://www.drugs-forum.co.uk/forum/showthread.php?t=17894