Last fall I mixed up at a 4 to 1 ration of gin and propolis. During the cold season I would take a few drops each morning. During last winter I did not get any of my average of 2 colds. Once summer hit I reduced my intake back to about once a week.
Last week my wife got a summer cold and I convinced her to try about 1/2 teaspoon several times a day. She said that it seemed to help how she felt for a while.
When she started coming down with this cold I went back to a few drops per day. So far so good