Ampicillin is excreted from the body primarily by the kidneys. In the first 6 hours after oral administration, up to 30 is excreted in the urine, and after intramuscular administration, up to 60-70 is excreted within 12 hours. Concentrations in urine are very high: from 150 to 3000-6000 mcgml, which is many times higher than the content in the blood.