Is it permitted to enter a non kosher restaurant in order to attend a medical conference/meeting? (of course no eating!) Thanking you.
If your attendance is important It is permitted for enter the restaurant for this purpose.
Nonetheless, it is generally preferable to avoid this.
In principle it is not permitted to eat in a non-kosher restaurant. The reason for this is the problem of maris ayin – it looks like the person is transgressing an issur by eating in the non-kosher establishment.
However, Rav Moshe Feinstein (2:40) writes that where a person is hungry and in a state of discomfort, it is permitted to eat kosher food in the restaurant, on condition that this is done privately in a way that his friends don’t see him, and that he tells those who see him that he was in a state of discomfort.
Shut Minchas Asher (67) goes a step further and writes that for business meeting there is no prohibition on entering the restaurant, because people understand that business meetings are held in non-kosher establishments even when no non-kosher food is eating, and there is no reason to assume that the person will be suspected of eating non-kosher food.
He adds that it is also possible that the prohibition of mar’is ayin doesn’t apply here, because we do not add circumstances of mar’is ayin that Chazal didn’t mention. This depends on a dispute between the Magen Avraham (463:4) and other authorities (see Peri Chadash, Yoreh De’ah 87:7; Peri To’ar 9).
Therefore, if attending the conference is important, either for reasons of parnassah or for reasons of education, one can be lenient and attend. However, it remains preferable to avoid entering and sitting in a non-kosher establishment, to distance oneself from mar’is ayin.