Depending on the cause :-
1) Try using a netipot : details are available on oprah.com - Dr Oz explained how it works on the Oprah Show, & had a member of the audience try using it - she later reported back having excellent results.
2) Avoid dairy products when you feel catarrh becoming a problem : my Scottish grandmother advised this when we were young, & she was right!
I use tablets by New Era. 'a homoeopathically prepared biochemic remedy' for catarrh & sinus disorders. available in good health shops - I have a tub in the car & tub in the house for when I need them xxx