What's the best thing to take for a dry cough?

Depends: We often forget that coughing is a protective mechanism; it protects our lungs from mucous leaking down the wrong pipe. However, if one needs cough medicine (such as to allow for sleep, ) one can take Robitussin-DM at night only. Don't take more than instructed and see your doctor if the cough worsens, is associated with a fever, or is not improving after a few days. Lots of water as well.

Depends on cause: A dry cough could be a symptom of a variety of different problems including sinusitis, allergies, esophageal reflux, side effect to medications like ace-inhibitors (a class of blood pressure medicine), inhalation of irritants, or congestive heart failure, and many other problems. Best to see your doctor to find and treat the underlying cause of the cough.

Options: Dry coughs can be difficult and interrupt sleep/daily functions. I tend to use a medication in an inhaler called ipratropium (atrovent). It can be given three or four times daily, is safe and has been shown to be effective in chronic non productive cough. It too can dry but it is non addicting and safer than narcotic containing anti cough medications.

Dry Cough: Often a 'dry cough' is caused by a sinusitis thats causing an irritating post nasal drip. Try some benadryl (diphenhydramine) (particularly at night as it may cause some drowsiness), gargle with some salt water and menthol. If the PND is from allergic reasons then claritin or zyrtec work well.