Let's take a minute to talk about your medication. 

This is metronidazole. It treats infections caused by certain bacteria and protozoa. It cannot treat infections caused by viruses, like the common cold. 

You should take this medicine exactly how your doctor tells you to. You should take each dose with a full glass of water. It is important to not miss doses, and to take it for as long as your doctor recommends. 

Most people tolerate this medicine well. Common side effects include a mild headache, nausea, diarrhea, and a change to the way food tastes. If it upsets your stomach, taking it with food may help. These effects are normal if they are mild and should go away. This medicine could make you a little dizzy or tired. You should wait until you know how it affects you before you do activities that require you to be alert, like driving. If these or other side effects become reasons you want to stop taking it, please talk to your doctor or pharmacist. 

As with any medicine, rare but more serious side effects could occur. You should tell your doctor right away if you notice any unusual changes to your body. You should also know that this medicine increased the risk of cancer in certain animals. The risk is not clear in humans. You should ask your doctor for more information if you have concerns.

Metronidazole can interact with other medicines. You should always check with your doctor or pharmacist before taking other medicines, even if they do not require a prescription. You should avoid drinking alcohol while taking this medicine and for at least one day after. Alcohol could cause a reaction that will make you feel very sick. 

For best results with metronidazole, let your doctor know if your condition does not improve.