The Chiyuv
7. One must become inebriated on Purim to the point that he cannot distinguish between ‘cursed is Homon’ and ‘blessed is Mordechai’ (שו"ע סי' תרצ"ה ס"ב ). In other words, a person must express praise and gratitude to Hashem for both Homon’s downfall and Mordechai’s ascent. Therefore, Chazal said one should drink wine while joyously expressing praise and gratitude without pause until he gets to the point that he cannot distinguish between the two (ט"ז, מ"ב סק"ד ).
8. Simchoh shel mitzvoh. We are not commanded to get drunk and degrade ourselves, as the mitzvoh to rejoice is not about giddiness or idiocy (מאירי הובא בביאה"ל ד"ה עד ). One who knows that he will disgrace a mitzvoh or conduct himself frivolously would be better off not getting drunk (חיי אדם ). All the more so if there is potential for issurim, such as crude language or mingling with women r”l.
9. Sleeping. Some say one does not need to get very drunk. Rather, he should drink more than usual until he feels some of the effects of the wine and then go to sleep. When he sleeps, he cannot distinguish between ‘cursed is Homon’ and ‘blessed is Mordechai’ (רמ"א שם ). The sleep must be by day (הגר"ח קנייבסקי ), and after drinking enough that it was induced by the wine (רמב"ם פ"ב מגילה הט"ו, מקראי קודש פורים סי' מ"ד ).
Drinking and Tefilloh
10. Drank a revi’is of wine. If one drank a revi’is of wine in one go (מ"ב סי' צ"ט סק"ב ) outside of a meal (מג"א ), he should not daven until the effects of the wine fade (שו"ע שם ס"א ). A revi’is of wine within a meal does not intoxicate (מג"א ), but it all depends on how the person feels (מ"ב שם ). Even less than a revi’is of strong drink, e.g., whiskey or vodka, can intoxicate. Again, there is no fixed rule; it depends on how the person feels (מ"ב שם סק"א ).
11. Shosui. If one drank more than a revi’is of wine and feels that the alcohol is affecting his clarity of mind, even if he can talk without stuttering and would be able to speak in front of a king, he may not daven Shmoneh Esrei or say Shema or its brochos until the effects of the wine fade (שו"ע סי' צ"א ס"א ). He may still be counted for a minyan. If he fears he will miss zman tefilloh or tefilloh with a minyan, he may daven (מ"ב סק"ג ). On Yom Tov (מהרש"ל, מ"ב שם סקי"ז ) or Purim (מגן גיבורים ), when there is a mitzvoh to drink wine, he does not need to wait for the alcohol to wear off.
12. Drunk. If one drank wine or another alcoholic beverage and cannot walk properly or speak before a king without stuttering, he may not daven, even if he will miss zman tefilloh. If he davened in this state, he must daven again. Some say he may be counted for a minyan (אחרונים הובאו בפסקי תשובות הע' 19); others say he may not (מ"ב שם סק"י ).
13. If he is drunk, but can still daven from a siddur, some allow him to daven (רמ"א ס"ג ). Still, it is not proper to rely on this lechatchiloh (מ"ב סקי"ז ). However, if he did daven, he may rely on this and not daven again (דרכ"מ סק"ג ). He should not be counted for a minyan.
14. Drunk like Lot. One who is drunk like Lot, i.e., one who does not know what he is doing and whose actions are meaningless, is considered insane for all purposes and is potur from mitzvos. If he davened or made a brochoh, he is not yotzei whatsoever and must daven again after he becomes sober (מ"ב סקי"א ).
Bentching
15. One may bentch drunk, even if he is stuttering, as long as he is in a frame of mind fit to speak to a king (שו"ע סי' קפ"ה ס"ד וס"ה, ומ"ב סק"ו ). This is because people sometimes end up drunk after eating a full meal, yet the Torah obligates us to bentch regardless (מ"ב סק"ד ).
16. Zimun. It could be that someone in such a state who is bentching (see previous paragraph) can also count for a zimun (מ"ב סי' צ"ט סק"י ).
Vomited
17. Vomited everything. If, before saying a brochoh acharonoh, one vomited everything he ate or drank, he should not say the brochoh since there is no food in his stomach to make a brochoh on (נזירות שמשון סי' קפ"ד, שו"ת שבט הלוי ח"א סי' ר"ה הע' לסי' ר"ח ). This is like the halochoh that one may not make a brochoh acharonoh after the food he ate has already been digested (שו"ע סי' קפ"ד ס"ה).
18. Vomited some food. If one vomited some food, but he is sure some food stayed down and he still feels some level of satiation, he may make a brochoh acharonoh. If he is unsure whether any food stayed down, he should not make a brochoh misofeik.
19. Bentching. If one ate significantly more than a kezayis of bread, but is unsure whether he vomited everything, he should bentch since bentching is a mitzvoh de’oraiso. Due to his sofeik, it would be best if someone else could be motzi him.
20. Brochoh near vomit. Though it is repulsive, vomit does not have the status of human waste; one may say brochos nearby (מ"ב סי' ע"ו סק"כ ). If it smells very bad and its presence is disturbing, it is like waste and one may not make a brochoh within sight of it (מ"ב סי' ע"ט סקכ"ט ).
