Oil of Oregano Gel caps are what I use if I get the very rare sniffle, haven't had the crud for 10+ years, thank you Jesus!
Capsules are definitely more palatable than taking a dropper full of liquid oregano oil.
I had the first symptoms of flu many years ago.
The local health food store carries a Naturopathic remedy called Oscillococcinum.
The health practitioner there told me to drop the pellets under my tongue straight from the little tube they are packaged in and let them dissolve there. Because touching them contaminates the remedy coating. And because that insured the fastest direct absorption into the bloodstream.
The next day those slight symptoms were gone. I kept this up for another day and never got the flu.
There's a herb called Pau d'arco. It, as well as olive leaf extract, are natural antibiotics.
Unlike prescription antibiotics, those also fight virus.
The standardized extract of either herb was recommended because that insures the full concentration of the medicinal properties.
I haven't had a cold or the flu in many years since that first little episode of flu symptoms.
Herbs are my go-to straight from Father's medicine cabinet.