We did indeed. A species invasive to the US which happens to be an old (and actually very tasty) European remedy against coughs: the narrow-leafed ribwort http://en.wikipedia.org/wiki/Plantago_lanceolata
For a sore throat I recommend the good old malt candy. Works miracles.
There's no cure for a sniffles, though, afaik. Unless you try Coffni's Cure: http://www.gutenberg.org/files/24276...-h/24276-h.htm
(IMO one of the best SciFi written in the 20est century)