Cefdinir is a medication that belongs to the class of cephalosporin antibiotics and is used to treat bacterial infections such as bronchitis, pneumonia, and infections of the skin, ears, sinuses, throat, and tonsils. It works by killing bacteria or preventing their growth. Cefdinir comes in the form of capsules and suspension (liquid) to take by mouth, and it is usually taken with or without food every 12 or 24 hours for 5 to 10 days, depending on the condition being treated. It is important to take cefdinir exactly as directed by the doctor and not to take more or less of it or take it more often than prescribed. Cefdinir may cause side effects such as diarrhea, headache, or nausea, and in some cases, it can be severe. It is important to tell the doctor or pharmacist if you are allergic to cefdinir or any other cephalosporin antibiotic, or if you have any other allergies.