Do not use this medication if you are allergic to Amoxil or to any other penicillin antibiotic, such as ampicillin (Omnipen, Principen), carbenicillin (Geocillin), dicloxacillin (Dycill, Dynapen), oxacillin (Bactocill), penicillin (Beepen-VK, Ledercillin VK, Pen-V, Pen-Vee K, Pfizerpen, V-Cillin K, Veetids), and others. Before using Amoxil, tell your doctor if you are allergic to cephalosporins such as Ceclor, Ceftin, Duricef, Keflex, and others. Also tell your doctor if you have asthma, liver or kidney disease, a bleeding or blood clotting disorder, mononucleosis (also called "mono"), or any type of allergy. Amoxil can make birth control pills less effective, which may result in pregnancy. Before taking Amoxil, tell your doctor if you use birth control pills. Take this medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Amoxil will not treat a viral infection such as the common cold or flu. Do not give this medication to another person, even if they have the same symptoms you do. Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.