Clindamycin is used to treat a wide variety of bacterial infections. It is an antibiotic that works by stopping the growth of bacteria.This antibiotic treats only bacterial infections. It will not work for virus infections (e.g., common cold, flu).ow to use clindamycin HCl. Take this medication by mouth with or without food, usually 4 times a day (every 6 hours), or as directed by your doctor. Take it with a full glass of water (8 ounces or 240 milliliters) unless your doctor directs you otherwise.