took doxycycline for twice a day for 10 days 100mg. had lots of vomiting, ( even with out warning), nausea, dry mouth, lost my taste and when i could taste i had a metal taste or a very horribe taste in my mouth. Also very tired, and wanted to sleep a lot. hot did not know this was what caused the problem until i went back to dr. i had finished the entire 10 days!! Still havent gotten my taste back and still feel nausea a lot and i took the last pill on Friday morning Aug. 26, 05. I think it did something to my taste!!! I still am not better. I was given it for broncitus. Still have upset stomach too.