Consumer advocate Ralph Nader yesterday criticized the medical profession for concentrating on the treatment of disease and accident victims rather than on prevention.

Speaking before a standing-room crowd of more than 300 at the Harvard-affiliated Beth Israel hospital, Nader said physicians tend to steer away from preventive medicine because of the "low prestige" accorded doctors in that specialty.

"For every ten people interested in working in areas of prevention, only one has the self-confidence to stand up to the low prestige," he said.

Focusing on such areas as nutrition and highway safety, Nader urged medical students in the audience to consider careers aimed at investigating the effects of harmful additives in food and at making highway travel safer.

"I think it's fair to say that if just ten physicians back in the 1930s had spent their full time helping to engineer safer highways, we would have about one-fifth of the highway casualties we have today," Nader said, adding that another reason doctors are reluctant to research prevention in these areas stems from a desire not to confront big business.

"When a prevention for something like malaria is found, the general consensus is that it should be implemented. But when you try to investigate the reasons for the nation's number one cause of epilepsy--automobile accidents--you have to deal with General Motors," Nader said.

In an interview following his speech, Nader said that while he sees part of the responsibility for these reforms as falling on institutions like the Medical School, the initial actions must came from individuals, and that "institutions will only respond when pressured."

During his hour-long speech at the Beth Israel, Nader suggested that medical students band together to form a "tithing" program in which students pledge to use a certain percentage of their salaries as doctors toward investigating areas of preventive medicine.