We all know that flu season can be terrible. Tens of millions of people get sick. Hundreds of thousands are hospitalized. Tens of thousands die

There are financial costs, too. In America, flu season drains some $90 billion out of the economy, including the cost of lost productivity. (See our infographic on flu season at work here.)

But while the flu is certainly bad for business overall, it certainly isn't bad for every business. Here, three companies that thrive when your temperature rises:

1. Reckitt Benckiser

The British consumer goods company, which specializes in health, hygiene and home products, is the maker of Mucinex and Strepsils, a throat lozenge popular in the U.K. That product sold like candy during flu season, and the company just reported better-than-expected growth for the first three months of 2013.

According to the Wall Street Journal, overall revenue rose 7 percent in the first quarter, to $3.84 billion, while pharmaceutical revenue increased 20 percent.

"This has been one of the stronger cold and flu seasons in recent U.S. history," Investec Securities analyst Martin Deboo told the Journal. "Crucially, the season has been later and longer in duration than average and has persisted well into the first quarter." And for sellers of throat lozenges, that's clearly welcome news. 

2. Kimberly-Clark Corp.

A "personal care" corporation that specializes in diapers and bathroom paper products — you've surely heard of their Kleenex and Cottonelle brands — Kimberly-Clark Corp. seems to have made some real money off those of you who failed to wash your hands after riding the subway. (Or worse, if you were this kid.)

The company reported a 13 percent increase in first-quarters earnings, helped notably by thriving sales of Kleenex. The Journal helpfully connects the dots: "Sales volume for Kleenex and Cottonelle were both up double digits in the period, with Kleenex sales benefiting from an active flu season in the U.S."

The company profited $531 million, or $1.36 a share, up from $468 million, or $1.18 a share, a year earlier. Sales were so good, in fact, that the company raised its per-share earnings outlook for the rest of the year to $5.60 to $5.75, from $5.50 to $5.65. 

3. Quidel Corporation

You know a company that manufactures rapid diagnostic testing solutions and virology assays was going to have a productive winter in a particularly harsh flu season. Indeed, Quidel's revenue was up $53 million to $54 million in the fourth of 2012, well over the market forecast of around $44 million.

Quidel won't release its final 2013 Q1 information until tomorrow afternoon, but several months ago, they could already tell how flu season was shaping up: "We saw a sudden and early onset to this year’s influenza season," said the CEO in a Jan. 4 press release. "I am pleased, however, with how well we were able to respond to the increased and rapid demand for flu tests."