Mouthwash Use May Increase Your Risk for Developing Hypertension, Diabetes and Stroke
If your mouthwash contains the antibacterial chlorhexidine, you may be increasing your risk for developing hypertension, stroke and diabetes (by reducing the "good bacteria" (good flora) in your mouth that help create a very beneficial neurotransmitter known as nitric oxide (excellent podcast about the benefits of nitric oxide)). Note: Nitric Oxide relaxes our arteries to help maintain optimal blood circulation/blood pressure levels in our bodies, prevents blood clots, helps maintain our metabolism and also improves insulin sensitivity (among many other things in our bodies involving supporting our immune system, memory and learning). Thus, if you reduce nitric oxide levels in your body (by using chlorhexidine containing mouthwashes), this could increase your risks for developing high blood pressure, stroke and diabetes.
Bottom line: If you do not have a specific dental condition (i.e. severe gingivitis) that requires the medical use of chlorhexidine containing mouthwashes, then try to avoid them. Also, be aware that other mouthwashes may also contain other kinds of antibacterial agents that may disrupt levels of "good bacteria" in your mouth as well.