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About cefalexin - Brand name: Keflex

Cefalexin is an antibiotic. It belongs to a group of antibiotics called cephalosporins.

It's used to treat bacterial infections, such as pneumonia and other chest infections, skin infections and urinary tract infections (UTIs).

Cefalexin is only available on prescription. It comes as capsules, tablets or as a liquid that you swallow.

Key facts

  • You'll usually start to feel better in a few days, depending on the type of infection you have.
  • The most common side effects of cefalexin are feeling sick (nausea) and diarrhoea.
  • Do not take zinc supplements while you're taking cefalexin. Zinc can affect how cefalexin works in your body.
  • You can drink alcohol while taking cefalexin.
  • It's important to keep taking cefalexin until you've completed the course, even if you feel better.

Page last reviewed: 5 April 2023
Next review due: 5 April 2026