Tetracycline is a highly-efficient drug intended for the treatment of such health conditions as Helicobacter pylori, skin infection, urinary tract infections, as well as acne and respiratory tract infections. Tetracycline should be taken from two to four times a day unless the recommendations of your health care provider are different. If you have been prescribed the liquid form make sure you mix the medicine evenly before taking it and throw away any unused medicine that has expired. If you ever had an allergic reaction to minocycline, tetracycline, sulfites or doxycycline do not start taking this medicine as the same reaction is most likely to repeat again.