Cramer: Jittery over this stock? Lighten up

Cramer: Give me a break, FedEx is delivering

Investors shouldn't worry about FedEx's missed earnings, CNBC's Jim Cramer said Wednesday, citing changing shipping routes and the company's strong stock performance. 

Still worried? Cramer has a prescription for that.

"You ever hear of Xanax?" Cramer said on "Squawk on the Street." "It's a franchise that could be unique to these hedge fund managers who are jittery about something like FedEx. Go take a Xanax."

(Read moreFedEx earnings fall short of expectations )

FedEx reported quarterly results on Wednesday that missed Wall Street estimates because revenue declined at its express delivery service, the company's biggest unit, as customers chose less speedy shipping options.

Officials at FedEx said it expects shipping volumes will bounce back during the holiday season. Despite a worse-than-expected most recent quarter, FedEx projects between 8 and 14 percent earnings-per-share-growth in the full fiscal year. The company has bought back 10 million shares of stock as of this year, which could have driven its earnings-per-share growth.

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Cramer attributed the missed earnings to companies that rely on shipping, such as Amazon, moving distribution centers closer to customers and eliminating the need for express delivery services.

"The urgency is not as important given the fact that Amazon has a warehouse next to your house," Cramer said. "You don't have to do expensive. The logistics of the country are now betting in your favor that you don't have to pay up."

(Read more: Cramer on Amazon drones: 'It could be like World War Z')

FedEx's stock has risen nearly 50 percent in the past year, reaching a 52-week high of $140.97 on Monday.

"What makes people happy?" Cramer said. "A stock that goes from $85 to $138, that's not good enough for people? What do people want?"

—By CNBC's Jeff Morganteen. Follow him on Twitter at @jmorganteen and get the latest stories from "Squawk on the Street." Reuters contributed to this report.