Please consult your physician before taking any medication. Generic Name: cephalexin (sef a LEX in) Cephalexin is in a group of drugs called cephalosporin antibiotics and is used to fight bacteria in the body. It works by interfering with the bacterias cell wall formation, causing it to rupture, and killing the bacteria. Cephalexin is used to treat infections caused by bacteria, including upper respiratory infections, ear infections, skin infections, and urinary tract infections. Cephalexin may also be used for other purposes not listed in this medication guide. Before using cephalexin, tell your doctor if you are allergic to any drugs (especially penicillins), or if you have kidney or liver disease, a stomach or intestinal disorder such as colitis, diabetes, or if you are malnourished.