I would say look for Robitussin (often called 'robo') gels. Robo liquid can be a backup but contains other junk such as artificial sweeteners and stuff that I don't like to ingest. For the robo liquid, it should be one that says only 'cough', not 'cough and' something else such as headache, chest, congestion, etc. The 'cough' generally means that robo contains DXM. The 'and' often means it contains some other active ingredient that is not desireable for research purposes.