Ampicillin is an antibiotic in the Penicillin Family. Ampicillin is a very common antibiotic that is used to treat many different kinds of infection.
Ampicillin is rarely used to treat acne. There is limited evidence about the efficacy of Ampicillin for treating acne symptoms. Antibiotic susceptibility testing indicates that the acne-causing P. acnes bacterium tends to be highly sensitive to antibiotics in the Penicillin family, including Ampicillin.
Ampicillin should not be used by people that are allergic to Penicillin family antibiotics (eg. Penicillin V, Amoxicillin) due to an increased risk of side effects.