In the early 1980s, a new method of extracting bile from living bears was developed in North Korea. In 1983, Chinese scientists imported this technique from North Korea.

According to the Animals Asia Foundation, the most original method of bile extraction is to embed a latex catheter, a narrow rubber pipe, under the bear's skin and surgically attach it to the gall bladder. In this way, the farmer can extract the bile through the end of the rubber pipe, which exits the skin at the top of the bear's thigh. The Moon Bear Rescue Center has received a number of bears with these "old-fashioned" latex catheters. The main problem with the latex catheter technique is that it became easily clogged with bile granules and other foreign matter and is therefore not an effective extraction method. In the mid-1980s, this technique was phased out.

The metal jacket technique followed. Here a rubber pipe connects to a fluid bag inside a metal box, held in place under the bear's abdomen by a metal jacket. The bile drains through the rubber pipe into the protected fluid bag and is emptied approximately every two weeks by the farmer.

This brutal method was found on the two bears rescued from a bear farm in Tianjin in January 2004, said Zhe Ke, an official of the Moon Bear Rescue Center in Sichuan Province. In addition to the pain and risk of infection, the metal jackets, which weigh in excess of 10 kg each, would also cause massive hair loss and painful skin irritation.

The metal jacket system was followed by a metal catheter technique. Here a six-inch catheter is surgically implanted into the bears' gall bladder, allowing farmers to milk the bears each day. During milking, the bears are tempted by food to lie flat on the bottom of the cage. Often, a metal grid is lowered on top of the bears to force them to remain in this flat position until the farmers finish. In many cases, the grid has never been raised.

"We have been horrified to receive many bears in cages with metal grids rusted permanently in the lowered position, pinning the bears flat to the bottom of the cage for years on end," Zhu said.

In recent years, Chinese bear farmers have introduced a new free-dripping method of bile extraction. This method uses no catheter but sees a permanent hole or fistula carved into the bear's abdomen and gall bladder, from which bile freely drips out.

During this type of bile extraction, the bears undergo the same treatment as the metal catheter method of extraction. As with the metal catheter technique, the bear is tempted by food or honey water to lie on the bottom of the cage and then the farmer forces an unhygienic tube into the gall bladder, breaking the membrane that has grown over the hole. This allows bile to flow directly into a bowl placed beneath. The damage caused by bile leaking back into the abdomen, together with infection from the permanently open hole, is as bad as the former methods and causes a high mortality rate on the farms.

"Unbelievably, our veterinary director has discovered during her surgical assessments that several of the bears we have rescued have been victims of every single method of bile extraction," Zhu told the author.

In January 2005, the Animals Asia Veterinary Team discovered that a new technique of bile extraction is now being tested on bears. Known as "fake-free dripping," farmers insert a permanent, perspex catheter into the fistula, which is almost impossible to see unless the abdomen is shaved and examined close-up. This new technique is against China's current regulations on bear farming.

"Harm to the bear's spirit is more cruel than that to its body. Every time I see those rescued bears who have suffered such pains and gone crazy, I feel so sorry and ashamed for humankind," Zhu said.