It's said to be effective in treating upper respitory infections.
Direction: Put few drops of 3% hydrogen peroxide (H2O2) into one ear. You will hear some bubbling, and may be a slight sting sensation, which is normal. Wait for the bubbling and stinging to subside (5-10min), then drain onto a tissue and repeat with the other ear.
This can be effective 80% of the time, especially treated at the onset of the symptoms (within 12-14hr)1.
Other amazing uses of hydrogen peroxide are here.