Take this medication by mouth as directed by your doctor, usually 4 times a day (every 6 hours). Take ampicillin on an empty stomach (1 hour before or 2 hours after a meal) with a full glass of water. Drink plenty of fluids while using this medication unless your doctor tells you otherwise.

The dosage is based on your medical condition and response to therapy.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

Continue to take this medication until the full prescribed amount is finished even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.