If you are visiting a spanish speaking country and you need to ask for cold medicine you must say:
-Tiene alguna medicina para el resfriado? (do you have any cold medicine?)
Here I will list some more sentences and vocabulary that might be useful:
-Estoy resfriado (I have a cold)
-Estoy congestionado (I have runny nose)
-Tengo tos (I have cough)
-Tengo frio (I am cold)