Bacterial infections refer to a variety of inflammatory conditions caused by bacteria entering the body. Inflammation caused by bacterial infection includes local inflammation and systemic inflammation, local inflammation such as tonsillitis, pneumonia and cystitis, etc., and systemic infection includes septicemia and so on. Generally, bacterial infections will cause local redness, swelling, heat and pain, as well as purulent changes, and may be accompanied by fever and chills and other systemic manifestations. Generally, bacterial infection can be detected through routine blood tests and bacterial culture, and the rise of white blood cells, neutrophils and C-reactive protein in routine blood tests suggests infection. The exact evidence of bacterial infection is culture. Positive results indicate bacterial infection. Bacterial infections need to be treated with targeted antibiotics, such as penicillin for purulent tonsillitis caused by streptococcus. Medications need to be administered under the direction of a physician and should not be used without authorization.