Fish can be eaten after taking cephalosporin. If the patient has no history of seafood allergy such as fish, no reaction will occur if fish is eaten after taking cephalosporin. If the patient is allergic and easily allergic to seafood, he or she should not eat fish. Because eating fish may cause allergic reactions to occur, such as a rash around the body, like hives or drug rash, which cannot be identified at this time and affects the continued use of cephalosporin. Other patients with allergic rhinitis or allergic asthma may also experience symptoms that cannot be identified as drug-induced or food-induced, and in severe cases, may even experience anaphylaxis. There will also be an impact on the treatment of the patient, because when an allergic reaction occurs, anti-allergic drugs such as hormones need to be applied, which will then affect the treatment of the primary disease. Patients should not eat fish if they are allergic, but they can eat fish if they do not have allergies.