Get emergency medical help if you have signs of an allergic reaction to Keflex (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).
Call your doctor at once if you have:
severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);
unusual tiredness, feeling light-headed or short of breath;
easy bruising, unusual bleeding, purple or red spots under your skin;
a seizure;
pale skin, cold hands and feet;
yellowed skin, dark colored urine;
fever, weakness; or
pain in your side or lower back, painful urination.
Common Keflex side effects may include:
diarrhea;
nausea, vomiting;
indigestion, stomach pain; 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.
 Keflex side effects (more detail)
