Mondelez International Inc., the maker of Oreo cookies, Cadbury chocolates and Ritz crackers, announced Wednesday that its revenue was down in the fourth quarter and for the full year in part because China's appetite for the crème-filled sandwich cookie fell. Distributors had excess biscuit inventory, Mondelez reported.

Oreo has been one of the country's most popular cookie brands since it launched in China in 1996, with Mondelez holding the largest market share in China's biscuit segment at 16%, according to market-research firm Euromonitor International. Cookie sales in China have more than tripled from 2003 to 50.4 billion yuan, or roughly $8.3 billion, last year.

But industry watchers say China is one tough cookie, and Mondelez is facing bigger obstacles to growth here.

Consumers in the world's most populous country are curious and willing to try out new things, but that means as more brands enter the market, there are more snacks to distract them from Oreos, said Ben Cavender, a senior analyst at consultancy China Market Research in Shanghai.

Mr. Cavender said most companies are finding that Chinese consumers bore easily, so it's key for food makers to innovate and introduce new brands. 'You have to keep the market constantly hooked,' he said, noting that changing the packaging often isn't enough.

Mondelez has been broadening its distribution channels, expanding deeper into China's biggest cities and working with well-known figures such as former basketball star Yao Ming to promote its brands. The company has also been innovating, stocking store shelves with mini-Oreos, Ritz crackers and Chips Ahoy cookies in portable cuplike packages that resemble ramen-noodle containers. There are also more flavors in China than ever before, including green tea and birthday confetti.

Consumers like Zhou Mengmeng, who says she's stopped buying Oreos because she doesn't think they're healthy, pose another problem. Ms. Zhou, a petite 24-year-old from central Henan province, said Chinese people who ate a lot of packaged food several years ago have stopped. 'We just didn't know they weren't that good for you,' Ms. Zhou said, noting that she's since switched to eating more fruit.

Mondelez executives have said they are aware that Chinese consumers are becoming more health-conscious. To address that concern, the company developed a cracker line, Pacific, with flavors such as sesame and red date are typically associated with health and traditional Chinese medicine.

Some other international biscuit makers are gaining ground in China, such as Korea's Orion Confectionery Co., which sells Choco Boy mushroom-shaped biscuits and the Choco Pie sandwich snacks, and Japan's Ezaki Glico Co., maker of the Pocky multi-flavored chocolate-coated pretzel sticks. Orion boosted its share of the fragmented market to 2.8% last year, up from 1.3% in 2008, according to Euromonitor. Ezaki's market share rose to 2.6% from 1.7% in the same period, according to Euromonitor.

Mondelez reported a profit of $1.77 billion, or $1 a share, in the fourth quarter, up from $569 million, or 32 cents a share, a year earlier. The company has said it is investing in emerging markets like Brazil and China, as well as restructuring to improve cost structure.