<prompt> Acid Labile penicillin is-CloxacillinFlucloxacillinMethicillinPhenoxy Methyl penicillin  <response>: Ans. is c i.e., Methicillin o Gastric acid destroyes the penicillins and decreases their bioavailibility. o All penicillins are acid labile accept phenoxymethyl penicillin penicillin V, Cloxacillin, Flucloxacillin, Oxacillin, Dicloxacillin, ampicillin. Note - Cloxacillin, flucloxacillin, oxacillin, and dicloxacillin are resistant to both acid as well as penicillinase. 