Catarrh and sinus problem?

Can any one offer any suggestions for the Relief of catarrh. I have suffered from this for 2 years. I use decongestant sprays antihistamine tabs, steam etc. These sometimes help but for only short periods of time. Not to be too graphic but the catarrh is always green so this would indicate that it is infected.I have tried antibiotics from my doctor which did nothing at all. I would be most grateful for any sensible suggestions.