Avodah Zarah 29A

לחספניתא, וחילופא סכנתא.

for facial wounds, but the reverse presents a danger.

חלא לסיבורי, ומוניני לתעניתא, וחילופא סכנתא. תחלי וסיבורא סכנתא, אישתא וסיבורא סכנתא, כאיב עינא וסיבורי סכנתא. שני לדג דם, שני לדם דג, שלישי לו סכנתא.

Vinegar is good for one to consume after bloodletting, and eating small fish is good for one who has completed a fast, but the reverse is a danger. Eating cress and then undergoing bloodletting poses a danger. With regard to one who suffers from a fever and undergoes bloodletting, this poses a danger to his life. Similarly, one who suffers from pain of the eye and undergoes bloodletting endangers to his life. On the 2nd day after eating fish one may let blood, and on the 2nd day after letting blood one may eat fish. With regard to eating fish on the 3rd day after letting blood, or letting blood on the 3rd day after eating fish, both of these actions pose a danger.

תנו רבנן: המקיז דם לא יאכל חגב״ש ⁠— לא חלב, ולא גבינה, ולא בצלים, ולא שחלים. אם אכל, אמר אביי: נייתי רביעתא דחלא ורביעתא דחמרא, ונערבבינהו בהדי הדדי ונישתי. וכי מפנה ⁠— לא מפנה אלא למזרחה של עיר, משום דקשה ריחא.

§ The Talmud presents a series of health-related statements. A baraita states: One who lets blood may not eat the following foods, corresponding to the acronym ḥet, gimmel, beit, shin. That is, he may consume neither milk [ḥalav], nor cheese [gevina], nor onions [betzalim], nor cress [sheḥalim]. If he ate one of these, Abaye said: He should bring 1/4th-log of vinegar and 1/4th-log of wine and mix them together and drink the mixture. And when he defecates, he should defecate only toward the east of the city, because the odor of the excrement after that treatment is offensive. Since the wind does not usually blow from the east, it is less likely to spread the stench.