As medical investigations continue into the death of Heath Ledger, searchers are focusing on the sleeping pills found in his bedroom. Queries on "ambien side effects" spiked during a month when prescription drug reactions have already stirred up buzz.

The brouhaha over a cholesterol study press release prompted lookups for "vytorin side effects" earlier this month. The drug makers' unusual decision to delay the results, then bypass medical journals for a PR announcement was more the heart of the controversy, but that was enough to cause anxieties to rise and stocks to fall.

Also, the January tradition of health resolutions spurred a close look at supplements, including a surge investigating what possible reactions aspartame or muscle milk could cause.

For more serious ailments, side effects may be the trade-off to cure greater evil. However, a major policy shift by the Food and Drug Administration could relieve one pressing concern: The government agency now requires suicidal impulses be studied during clinical trials.

The Search box has been one way to sift through the medical claims. The list details the top 20 check-ups on meds and supplements, treating everything from high cholesterol to anxiety to sexual performance.