Ukrainian opposition leader and presidential candidate Viktor Yushchenko was the victim of poisoning by dioxin, his doctor said on December 11.

"There is no doubt about the fact that the disease was caused by poisoning of dioxin," said Michael Zimpfer, director of the Vienna Rudolfinerhaus hospital, where Yushchenko has been receiving treatment.

"There were high concentrations of dioxin, most likely orally administered," the doctor told a news conference at the hospital.

"We suspect a cause triggered by a third party."

Yushchenko, 50, spent a period at the Rudolfinerhaus clinic in September and October after falling ill for unknown reasons. The symptoms include severe stomach ulcers, spinal pains and disfiguring.

Yushchenko, who repeatedly claimed that he was poisoned by his political rivals, returned Friday to Austria to receive further treatment.

Source: Xinhua