Jews are not allowed to smoke, and they are required to observe a healthful way of life, said Rabbi Moshe Shaul Klein, rabbi of Bnei Brak's Ma'ayanei Hayeshuva Medical Center and representative of the halacha committee of one of the city's leading rabbinical arbiters, Rabbi Shmuel Wosner. Klein was addressing a conference of rabbis and hospital staffers on the subject of Medical Ethics and Halacha over the weekend. "Let's take the example of tobacco smoking. Anyone who is intelligent and offered a certain drink that just one out of 10 doctors says is poisonous would not drink it," said Klein, implying that smoking - which has incontrovertibly been proven deadly - is forbidden by Jewish law. A handful of rabbinical arbiters had previously stated publicly that it was forbidden to smoke; many others have ruled that it was forbidden to start smoking, but have stopped short of requiring those who already smoke give up the habit, while others say this only privately. Klein said at the hospital conference that the requirement to live a healthful life includes undergoing preventive tests for early diagnosis of disease, as survival rates are much higher when diseases are detected early. He endorsed mammographs for women and colonoscopies for both men and women who were over 50. Another leading rabbinical arbiter, Rabbi Yitzhak Zilberstein, took the conservative haredi view (contrary to that of national religious rabbis and some haredi rabbis abroad) that death - after which one may halachically take organs for transplant - means the cessation of heartbeat, and not lower-brain death in which the heart can continue to beat. He also attacked the phenomenon in some hospitals of demented kidney-failure patients being denied dialysis and other medical treatments. "There is no difference in giving medical treatment to a demented patient and one with a wise and acute brain," he said.