Very effective when properly prescribed, I felt improvement in my condition within 24 hours of starting a course of 1000mg, once daily. As it is winter, I didn't notice any of the photosensitivity mentioned as a side effect, but I did suffer some minor gastrointestinal upset. The main unpleasantness with this drug was due to the location of the infection, as the clearing sinuses drained into the back of my throat. I was left with the persistant taste of the antibiotic in my mouth almost constantly, with the taste disappearing only as it neared the time for another dose. Toothbrushing and breath mints only served to mask this temporarily. Not all that glamorous, but definitely effective.