Get emergency medical help if you have signs of an allergic reaction to tetracycline: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
severe blistering, peeling, and red skin rash;
fever, chills, body aches, flu symptoms;
pale or yellowed skin, easy bruising or bleeding;
any signs of a new infection.
Common tetracycline side effects may include:
nausea, vomiting, diarrhea, upset stomach, loss of appetite;
white patches or sores inside your mouth or on your lips;
swollen tongue, black or "hairy" tongue, trouble swallowing;
sores or swelling in your rectal or genital area; or
vaginal itching or discharge.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Tetracycline side effects (more detail)
