Manufacturers claim that effervescent medicines (such as Alka-Seltzer) are more easily absorbed into the blood stream and therefore effective at getting medicine to the body, fast. But a recent study also shows that many of those formulations pack in an astonishing amount of salt. If you take the full daily dose of some over-the-counter effervescent medicines, the study's researchers found, you'll end up getting more sodium that you're supposed to have in an entire day – and have a higher risk of stroke, high blood pressure, and heart attack.

The research team looked at data from more than 1.2 million people in the United Kingdom, following each for an average of about seven years. During the study, there was a total of roughly 61,000 heart attacks, strokes, and other major cardiovascular incidents. People who used effervescent medications, the researchers found, were 22 percent more likely to have a stroke than people using non-fizzy versions of the same drugs. People who took fizzy medicines were also seven times more likely to have high blood pressure than those who didn't. While the question of exactly how much salt we need is still a matter of debate, many experts agree that too much sodium can lead to high blood pressure – which, in turn, can lead to heart attack and stroke.

Some patients have difficulty swallowing pills, and they may need to take dissolvable medications. For everyone else, "avoid OTC preparations that have high salt content," recommends Dr. Jacob George, a clinical pharmacologist at the University of Dundee in England who led the study. "Add to [effervescent medicines] the typical Western diet and this would take most people way above what they need in terms of daily dietary sodium." Opt for a pill when you're under the weather, and leave space in your diet for a bowl of soothing – and, yes, maybe a little salty – chicken soup.

To add to the problem, fizzy tablets have been shown to degrade some medicine and supplements, including vitamin C, which degrades as soon as it begins to bubble. So not only will you be getting more sodium, you'll be getting less of a benefit.