"Merck is exactly the kind of company that investors circle the wagons around" during difficult macroeconomic events like long-lived government shutdowns, Cramer said on "Mad Money" amid a broader market rotation.
"Even though Merck ran up dramatically last year, I think the stock remains way too cheap, and as the rotation plays out, it could get even cheaper, meaning you could get an even better buying opportunity," he continued. "We're talking about a best-of-breed drug company here, yet it's not getting the kind of premium multiple I think it deserves."
So, even though Cramer expects more selling in the drugmakers' stocks in the next several days, he urged stock-pickers to consider the bigger picture and, if they're interested, to scale into Merck's stock "gradually."
"Thanks to Keytruda," Merck's leading anti-cancer franchise, "Merck is once again a growth pharmaceutical company," he said. "I'm betting it'll be years before their key drug faces any meaningful competition, which means you can buy it into weakness here."
Investors still have time to take advantage of the broad rotation out of "safe" food and drug stocks and into faster-growing stocks like the semiconductor plays, Cramer said Thursday.
The rotation involved people selling shares of companies like drugmaker Merck and spice guru McCormick & Co. and snapping up shares of chipmakers including Texas Instruments, Xilinx and Lam Research, all of which recently reported strong quarters. The mixed action resulted in a placid trading day for the major averages.
Why isn't it too late? Because, according to Cramer, a rotation is "rarely a one-day phenomenon."
Click here for how Cramer would play these moves.
Okta now has more than 100 million registered users, a major milestone for the 10-year-old software company, Okta co-founder and CEO Todd McKinnon confirmed to CNBC in an exclusive "Mad Money" interview.
"We're changing their world," McKinnon told Cramer on Thursday. "We're making it incredibly easy for them to connect to all their technology, whether they're logging into their business applications at work or they're a customer of one of our customers logging into a website."
Shares of Okta, which provides companies including Adobe and Twenty-First Century Fox with a secure, cloud-based system for managing employees' and customers' access to digital tools and information, climbed nearly 150 percent in 2018. It was also the second-best performing stock in the Russell 1000 index, which tracks large-cap companies.
According to McKinnon, the main factor driving Okta's success is the rise of cloud adoption, which he told Cramer is still in its "early days."
Click here to watch and read more about his full interview.
This earnings season is far enough along that investors can start making judgments about which stock market sectors are on the rise and which ones could see weakness in the better part of 2019, Cramer says.
"We need to be on the lookout for themes that are working in spite of the litany of big-picture negatives" including the turmoil in Washington, slowing global economic growth and the damage done by the Federal Reserve's "ill-advised" statements about interest rates in late 2018, Cramer told investors Thursday.
Click here for the seven themes that he thinks can inspire some strategic (and successful) investing.
United Rentals' current and future leaders are bullish on the success of their equipment rental business continuing into 2019, they told Cramer in an exclusive interview Thursday.
Mike Kneeland, the company's current CEO, is scheduled to step down in May and become chairman of United Rentals' board of directors. Matthew Flannery, the company's chief operating officer, will take over as CEO.
In the "Mad Money" interview, Kneeland highlighted a key shift in his company: 23 percent of the rental giant's business is now tied to specialty rentals, which occur at high volume and generate high returns, he said.
And even though the company is very acquisitive, having made nine acquisitions in the last two years, incoming CEO Flannery told Cramer that the balance sheet would remain strong through the integrations.
"By the end of 2019, even with all the acquisitions we've done, our leverage will be back down to the bottom of our range at 2.5 percent," he said.
Click here to watch Mike Kneeland and Matthew Flannery's full interview.
In Cramer's lightning round, he flew through his responses to callers' stock questions:
Kemet Corp.: "This stock was up as a corollary to Xilinx. It really doesn't have that much to do with it, but the ETFs drove it up. I think it's inexpensive. Look, it's a capacitor company. It's an inexpensive stock. I don't think you're going to get hurt. It's better, for instance, than Western Digital, which reported an OK number today and is actually rallying because people felt that they were going to say bad things and they didn't."
Charles Schwab Corp.: "We're getting a little weakness in that group. I did a piece last night — a lot of people were buzzing about it — about how that flash crash that we had in December, right before Christmas, is turning a lot of retail investors off. I've got to be a little more cautious about retail [investing] because the market is making me more cautious about what it's doing to people who invest. Without an investigation, of course. No investigation of anything."