bacterial infection
"Clindamycin is one of the oldest, safest, and most effective broad-spectrum drugs on the market.  It must however be taken as directed, meaning you should probably eat something before you take it, you must take the entire prescription, and follow proper dosaging instructions.  If you fail to do this, your infection can return, the bacteria can become resistant, which means the bacteria could become immune, and you will no longer be able to take this antibiotic.  As someone who is not able to take antibiotics like penicillin due to a life-threatening allergy, I consider this to be a wonder drug.  All drugs have contraindications (side effects), the least of which is stomach ache/GI issues."