Leading antibiotics maker Lukang Pharmaceutical <600789.SS> and North China Pharmaceutical <600812.SS> made rare appearances at the top A-share gainers list in Shanghai. A shares are off limits to foreign investors.

Accord Pharmaceutical <2028.SZ> was among the best B-share performers on the Shenzhen bourse, rising 0.56 percent to HK$7.19. Foreign investors can trade China's hard-currency B shares.

"It is not surprising to see retail investors buying stocks of antibiotics when the fear of anthrax is spreading around the world," said analyst Mary Zhang of Galaxy Securities.

US authorities have confirmed the presence of anthrax in Florida, New York, Nevada and Washington - apparently delivered in letters sent through the post.

Despite the share rally yesterday, analysts and company officials said they expected only a limited boost, if any, from the anthrax jitters as Chinese drug makers exported only materials, rather than manufactured products.

"Domestic antibiotic makers do not make vaccines, so the only benefit they might get is to ship more raw materials overseas if demand from foreign antidote makers rockets," Galaxy's Zhang said. But a surge in Chinese exports was unlikely, he added.

Anthrax antidotes are made by companies in Japan and India, but they do not export to the United States, which is scrambling to increase stocks of Cipro, the only approved oral treatment for the disease.

Cao Zhengping, spokesman for North China, said his company had not received fresh orders for exports since the outbreak of the anthrax disease.

The Shanghai B-share index fell 0.3 percent to 153.801 points as turnover slumped 44 percent to US$13.47 million, the lowest since March 2.

The Shenzhen B-share index edged down 0.59 per cent to 248.78 on a three-week low turnover of HK$117.63 million as the A-share downtrend showed no signs of ending.

Domestic A shares, off limits to foreign investors, finished down nearly 1 percent as a spreading government crackdown on market corruption continued to sideline most investors, brokers said.

But Sinopec Shanghai Petrochemical <600688.SS> <0338.HK> outperformed the index after Sinopec <0386.HK> <600028.SS> said China had linked oil product prices to markets in Rotterdam, New York and Singapore to reflect better international prices.

Industry analysts said the news was positive for Sinopec, China's largest refiner, but said it was still too early to assess the exact impact on its bottom line because they did not yet have details on how the new pricing formula would work.

A shares in Shanghai Petrochemical, which also has refining business, inched up 0.81 percent to 3.72 yuan (44.9 US cents). Sinopec's A shares ended up 0.54 percent at 3.71 yuan (44.8 US cents).

The Shanghai composite index lost 12.836 points to 1,643.066 as turnover slimmed 15 percent to 3.4 billion yuan (US$410.6 million).

The Shenzhen composite sub-index dropped 7.32 points to 3,323.58 as trading totalled 2.34 billion yuan (US$282.6 million), down 12 percent.