More than 135 million consumers visit Yelp.com each month to look at customer reviews and star ratings that help them choose restaurants and other local businesses. But Yelp may be withholding some information that you need to make good choices.

Reason: Yelp uses automated software that sorts through millions of reviews and aggressively suppresses any it decides are fake. That’s fine if it catches only the fake ones. The problem is that about 20% to 25% of all reviews are flagged as suspicious and removed, even though Yelp acknowledges that many of these may be authentic.

Yelp says that this vigilance is necessary to protect consumers. The company says it scans for measures of “quality, reliability and activity.” Also, it says the filter can detect various inappropriate incentives—for instance, businesses that offer discounts to individuals if they leave a five-star rave on Yelp…or businesses that pay freelancers to malign their competition with one-star rants.

Yelp’s controversial filtering has generated 2,000 Federal Trade ­Commission complaints from local businesses and spawned several lawsuits. Recently, however, a federal appeals court ruled that Yelp has a legal right to decide which reviews to feature on its site and how to present them.

To get the most com­plete picture…

Read the suppressed reviews yourself. Yelp doesn’t delete the reviews that it filters out—it hides them. They still are accessible by clicking the “not currently recommended” link at the bottom of each business’s page.

Use common sense to decide which hidden reviews to ignore. Fake reviews overwhelmingly tend toward the extreme. They often award a business one star or five stars without providing any good reasons why. Or they use over-the-top language such as “the best/worst ever.”