Belgian scientists have found that library books might have more on them than just dust mites.

Here’s one to file under the Gross Yet Somehow Unsurprising section in your mental filing cabinet. We all heard last year about the horrors of bedbugs in libraries, but two professors in Belgium recently undertook an investigation into exactly what grody items are crawling all over your favorite library books.

Jessica Roy writes for Time that the professors—experts in toxicology and bacteriology—found the ten most popular books at the Antwerp library and screened them for germs and other substances. All ten of the titles ended up testing positive for traces of cocaine, which suggests that Belgian library patrons are having just the BEST time when they borrow, say, Wuthering Heights or the latest offering from Sue Grafton. In all seriousness, Roy reports that the drug wasn’t present in large enough quantities for unsuspecting patrons to feel any effects, but they could end up testing positive for cocaine.

The copies of 50 Shades of Grey, meanwhile, produced even cringe-inducing results, in the form of the herpes virus. E.L. James’s wildly popular erotic novel apparently tested positive for traces of the virus, albeit in minimal enough quantities that the professors assure that there’s no public health risk and no possibility of contracting the STD from contact with the book.

Still, the coincidence of finding a sex disease on a smutty book does make you wonder about what you might find on other books, and make you think twice about borrowing, for example, Dracula (for fear of the blood of the undead), Moby-Dick (smelly ambergris), or Albert Camus’s classic The Plague.