Oral metronidazole should be taken after a meal because it can cause serious gastrointestinal discomfort, so taking it after a meal can reduce the reaction to the gastrointestinal tract. Metronidazole is an anti-anaerobic antibiotic that is commonly used in the oral cavity to prevent infection after tooth extraction and to control infection during periodontitis and periapical inflammation, and is also a common anti-infective drug used in dentistry. When using metronidazole in the oral cavity, it is important to use these antibiotics in conjunction with routine oral treatment, such as painful pulpitis, painful periapical periodontitis, painful wisdom tooth pericoronitis, etc., when the corresponding treatment of the tooth is required. Then you can use other antibiotics such as metronidazole in conjunction with them so that you can achieve better treatment results.