12. I Told You Before, Ah, You Can’t Eat That: The prohibition against eating any chometz at all..

The prohibition is not to eat anything containing any chometz whatsoever, even if it’s not a main ingredient. The punishment depends on the quantity of chometz in the mixture. If it is less than an olive-sized amount of chometz to “half a loaf” of non-chometz (a quantity equal to three or four eggs in volume), the mixture would be prohibited, but it would not subject a person to the penalty of lashes.

The purpose of this mitzvah is to reinforce the severity of eating chometz on Pesach. In order to impress upon us the seriousness of this prohibition, the Torah forbids it even to this degree.

Nachmanides (the Ramban) did not include this among the 613 mitzvos, considering it included in the general prohibition to eat chometz on Pesach. The Rambam and Ramban also differed on whether such a mixture could lead to the penalty of kareis (spiritual excision – Ramban says yes, Rambam says no), but everyone agrees that it is prohibited under Torah law.

This mitzvah applies to both men and women in all times and places. It is #198 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos #5 of the 194 negative mitzvos that can be fulfilled today in the Chofetz Chaim’s Sefer HaMitzvos HaKatzar. In the Talmud, it is discussed in Pesachim 43-44 and it is codified in the Shulchan Aruch in Orach Chaim 442.