1. For the treatment of sensitive enterococci, Shigella, Salmonella, E. coli, Listeria, aerogenes, Haemophilus influenzae and Proteus mirabilis.
2. Broad-spectrum semi-synthetic penicillin drugs, low toxicity. Similar antibacterial spectrum and penicillin, penicillin-sensitive bacteria lower potency, antibacterial effect viridans with penicillin similar or slightly stronger. Against diphtheria, tetanus, and actinomycetes its effectiveness and penicillin basically the same. Enterococcus and Listeria effect is better than benzylpenicillin. And it can produce drug-resistant staph bacteria penicillin had no antibacterial effect. Effective against gram-negative bacteria, but easy to produce drug resistance.
3. Mainly caused by susceptible strains of the drug for urinary system, respiratory system, biliary tract, intestinal infections and meningitis, endocarditis.
4. Mainly used for typhoid, paratyphoid treatment; also for the urinary tract, respiratory tract infections.

It is used for the treatment of infections known to be or highly likely to be caused by these bacteria. These include common respiratory infections including sinusitis, bronchitis, and pharyngitis, as well as otitis media. In combination with vancomycin (which provides coverage of ampicillin-resistant pneumococci), it is effective for the treatment of bacterial meningitis. It is also used for gastrointestinal infections caused by consuming contaminated water or food, such as Salmonella, Shigella, and Listeriosis.
Ampicillin is a first-line agent for the treatment of infections caused by Enterococci. The bacteria are an important cause of healthcare-associated infections such as endocarditis, meningitis, and catheter-associated urinary tract infections that are typically resistant to other antibiotics.