Before you can order Ampicillin online, your local doctor needs to know if you have any of these conditions: bowel disease, like colitis, heart disease, kidney disease, liver disease, seizures disorder, an unusual or allergic reaction to ampicillin, other penicillins or antibiotics, other medicines, foods, dyes, or preservatives, pregnant or trying to get pregnant, breast-feeding. Patients with a history of allergic reactions to other penicillins should not buy Ampicillin. Persons that are allergic to the cephalosporin category of antibiotics, which are related to the penicillins, for example, cefaclor (Ceclor), cephalexin (Keflex), and cefprozil (Cefzil), may or may not be allergic to penicillins.