I've found out that the homeopathic sites are pretty dead on about thyme. With Eric coughing and hacking from a Christmas cold, and no help at all from the codeine laced drugs he got at the doctor's, we decided to turn to the Old Ways.
Fresh thyme apparently contains the chemical that is extracted for pertussin in cough medication and it has the property of calming those annoying spasmodic coughs that trail for days at the end of a cold. Wemixed it with some lemon zest and made it into a quite tasty tea that worked like a charm, stilling the nighttime coughing fits.
Lemon Thyme Tea
2 Tbsp chopped fresh thyme
1 tsp lemon zest
2 cups hot boiling water
Let the thyme and lemon zest steep in the water for several minutes, then strain it out and drink the tea.
I sewed dosages of it into coffee filters to make teabags we could carry with us.