your doctor knows if you have ever had an allergic reaction to any cephalosporin antibiotic such as Keflex?? or Ceclor?? before you take piperacillin.Make sure your doctor knows if you have mononucleosis (mono), stomach or intestinal disease, asthma, liver or kidney disease, cystic fibrosis, hay fever, or other allergies before you take this medicine.Make sure your doctor knows if you are pregnan