Eggs are not the only commodity suddenly out of kilter. Domestic prices and trading volumes on steel, garlic, cotton, iron ore and other items have all soared. This despite the fact that China’s economic slowdown has hurt demand for many items. Officials at Chinese commodities markets are now taking steps to cool speculative fervor to avoid crashes, and prices have begun to ease.

By mid-April, the frenzy made Shanghai futures contracts in steel rebar, the rods used in construction to reinforce concrete, the most actively traded in the world — overtaking trading volumes of two major oil futures contracts, West Texas Intermediate and Brent crude, that have helped set oil prices for decades, analysts at Citigroup said in a report last week.

“There is very little rational or fundamental basis for why prices have gotten as out of hand as they have, or why volumes are so high, other than just irrational exuberance,” said Alex Wolf, an emerging markets economist at Standard Life Investments in Edinburgh, who previously worked as an American diplomat based in Beijing and Taipei.

Economists blame Beijing’s new efforts to shore up its economy. Government officials increased lending by state-controlled banks and offered other support measures in the first few months of the year as economic growth slowed and longtime drivers like manufacturing and exports showed continued weakness.

Saad Rahim, the chief economist at Trafigura, one of the world’s biggest traders of metals and oil, calculates that China added about $1 trillion in new liquidity in the first quarter of the year — an amount that would be roughly equal to the entire quarterly economic output of Germany during the same period.

“This kind of scale is unprecedented and some of it will leak into speculative investments,” Mr. Rahim said.

In the short term, the new lending may be good news for global growth, if it works. China’s first-quarter growth came in at 6.7 percent, about where economists had expected, despite some indications that growth had weakened further.