Hi! I use the liquid extract-- and if you use two drops under the tongue for 5 days a week, that may even be enough to stave off any potential sinus infections, colds, flus. -- just those two drops each night after brushing the teeth.

I also have used the gelcaps combined with peppermint oil from another company-- that cost $5.99 a box. The gel caps, I feel, are more effective with intestinal issues-- including parasites in the intestines.