Toilets are a private concern for most people in rural China, except when they become a major health concern.

For a Chinese farmer like Gao Zhiping living in a backward, mountainous region, talking about toilets is like talking about sex - it's a private concern and impolite to discuss.

For him, going to the toilet is part of life, but not nearly as important as the happiness of a good corn harvest or the benefits from subsidy policies.

But a national campaign to improve toilets and sanitation by the Chinese government on the basis of the United Nations Children's Fund's pilot program in the 1990s is changing Gao and his fellow Chinese peasants' ideas and actions.

Having lived in Gaojiagou Village, Xiangyuan County in northern China's Shanxi Province, for more than half a century, Gao is accustomed to the dirty environment of his toilet.

"When the summer comes, the toilet stinks, driving off passers-by. Flies are everywhere, over the roof, in the kitchen, you name it," Gao points to the shabby open toilet constructed by his grandfather in the early 1950s.

In Gao's village and the larger Shanxi Province, open toilets are common. Farmers build a simple toilet using flagstones, and most latrine pits are up to 2 meters high.

In some places, the villagers don't have a personal toilet and share an open toilet. But these large toilets can be dangerous for children - some have slipped into the pit and drowned, 53-year-old Gao says.

More alarming is the health threat from this type of open toilet. In the past when tap water was not available, Gao had to go far to fetch water from the Sishui River at the foot of the mountain. Underground water was polluted by the open toilets, which also leaked into the river. "We were worried, but no one knew how to deal with the situation."

Gao's village is not on its own. In the adjacent Dongchangyi Village, diarrhea was commonly reported in the past and there was a high incidence of cancer, says villager Wang Xianzhong.

One of the reasons behind the high occurrence of diarrhea, according to Wang, was that children had easy access to dung. "They liked to play games with it."

Game-playing like this is not funny. UNICEF reports that there are 190 million Chinese children suffering from roundworm and 70 million tormented by whipworm infections.

"These bowel infections can result in retarded growth and malnutrition," says Lei Jun, an official from UNICEF.