id say depends how much dxm you do and how much e your gonna take. if you do dxm regulary (multiple x's a wk) it could still be in your system in high enough doses to make Seretonin syndrome a real dander, and if your planning on taking alot of e even if you dont do dxm regulary it could still pose a threat. id say if u only did a little dxm yesterday and only planning like 1 e pill you should be straight, but im not a doctor thats just what id do.