Hebei Welcome Pharmaceutical Co and its affiliated company North China Pharmaceutical Group Corp on Thursday were found guilty by a United States court of fixing the prices of vitamin C products.

This was the first time that Chinese companies were on trial in the US for alleged antitrust violations.

The judge ruled that the two companies have to pay $162 million in compensation.

The Chinese vitamin C makers said in their legal defense that the central government asked them to adjust the prices of exports products.

A judicial document was issued by China's Ministry of Commerce supporting the two companies' claims and urging the court to reverse the verdict, as the industrial policy in China allowed them to adjust the prices.

The plaintiffs in the case were an animal feed company in Texas and a vitamin C distributor in New Jersey. Both companies claimed that the Chinese companies formed an illegal price-controlling association, raising the prices significantly and bringing a loss of dozens of million dollars to US consumers. The products made by the Chinese companies are used in food, drinks and animal feed.

In the late 1990s, companies from Switzerland, Japan and Germany were also involved in vitamin C price-fixing cases in the US market. They were put on trial in the US and Europe and paid $1 billion in criminal compensations and over $1 billion in civil compensations.

The annual sales volume of vitamin C products in the US market exceeds $100 million, court documents showed.