It all started a few years back. Menachem was sitting with a group of friends, one evening. As the boys began to talk, one boy, Yaakov dug into his pocket, and pulled out a pack of cigarettes. He held out the box to the rest of the group, and each boy took one, except for Menachem.
"Menachem, why aren’t you taking one?" Yaakov asked.
"I… I don’t smoke" Menachem responded, hesitantly.
"Why don’t you just try it once?" urged Baruch. "What do you think will happen?"
And so, Menachem took one cigarette. That one was followed by another one, and then another. It didn’t take long for Menachem to develop a liking to this new habit, and soon he was buying his own cigarettes.
One morning, Menachem woke up with a bad cough. His mother, upon hearing Menachem’s incessant barking, over the phone, insisted that he go to the doctor. Menachem dutifully made an appointment, and made his way to Dr. Newman’s office.
As Dr. Newman examined Menachem, he inquired "tell me, Menachem, do you smoke?" When Menachem answered in the affirmative, Dr. Newman continued "Menachem, you’re young. You have your whole life ahead of you! Why do you want to start ruining your health now?! Menachem, I’m sending you down the hall for a chest x-ray. Once you’ve done it, please come back to me with the results."
Menachem left the doctor’s office, deep in thought. "What if I really am damaging my health? What if the doctor is right, and the cigarettes might make me very sick? But how can I stop smoking now? It’s become a part of my life!"
After a little while, Menachem returned to Dr. Newman’s office. Dr. Newman watched, as the x-ray image appeared on his computer screen. Amazingly, Menachem’s lungs were just fine! But how could Dr. Newman let Menachem leave the office, thinking that smoking wouldn’t hurt him in the long run?
Dr. Newman pulled up an image of another patient’s lungs, and swiveled the monitor in the direction of Menachem. "Menachem, you see all the black? That’s what those cigarettes are doing to your lungs! Please, find a way to stop smoking! If you stop now, you can still reverse the damage."
Menachem left the clinic, promising himself that he would do his best to quit smoking.
Was Dr. Newman correct? Was he permitted to lie, and pretend the other patient’s x-ray image was really Menachem’s, in order to get Menachem to quit smoking?
Rabbi Yosef Tzvi Rimon, shlita:
We are permitted to lie, under certain conditions, for the sake of peace. It follows, then, that it is definitely permitted to lie in order to save a life. This principle, that it is permitted to lie in order to avert possible danger, is demonstrated in a medrash regarding Yaakov and Esav.
When Yaakov and Esav met (see Bereshit 32:4-33:16), Esav requested that Yaakov and his family come with Esav. Yaakov was concerned that Esav intended to do harm to Yaakov and his family. Therefore, Yaakov said that he intended to go to Se’ir, when he actually intended to go to Succot. (See Yalkut Shimoni, Vayishlach, remez 150) In fact, Yaakov intended that the Jewish people would ultimately come to Se’ir in the time of Mashiach. (Yalkut Shimoni, Vayishlach, remez 148-149)
Based on this principle, it is permitted for Dr. Newman to lie to Menachem, in order to save his life. However, it is important that Dr. Newman only use this leniency when it is absolutely necessary, and there is no reasonable alternative. For example, Dr. Newman could show Menachem the real x-ray images, but could describe, in graphic detail, what Menachem’s smoking habit is liable to do to his lungs in the future. Additionally, Dr. Newman must be careful not to get into the habit of lying, for a number of reasons:
A) Every lie is problematic. It is likely to damage the person telling the lie, and his positive character traits. If there is an alternative to lying, it must be utilized.
B) It is important to not become accustomed to lying (see Gemara Yevamot 73a)
C) Lying is likely to cause additional, unintended consequences. (For example, the doctor might cause the patient to enter a state of panic, which could lead to further problems.)
D) If it becomes know that doctors lie, patients will begin to distrust doctors.
In summary: There is reason to allow Dr. Newman to show the other patient’s x-ray to Menachem, as a one-time exception. This is only if it is clear that Dr. Newman will not convince Menachem to quit smoking, otherwise, and that, in so doing, Dr. Newman will not cause greater harm, by, for example, causing Menachem to enter a state of panic or despair.