הָאִשָׁה מִתְטַמֵּאת בְּאֹנֶס בֵּין לְנִדָּה בֵּין לְזִיבוּת. כֵּיצַד. כְּגוֹן שֶׁקָּפְצָה מִמָּקוֹם לְמָקוֹם. אוֹ רָאֲתָה בְּהֵמָה אוֹ חַיָּה אוֹ עוֹף מִתְעַסְּקִין זֶה עִם זֶה וְחָמְדָה וְרָאֲתָה דָּם. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה הוֹאִיל וְרָאֲתָה דָּם מִכָּל מָקוֹם נִטְמֵאת וּמְטַמְּאָה בְּכָל שֶׁהוּא. אֲפִלּוּ רָאֲתָה דָּם טִפָּה כְּחַרְדָּל הֲרֵי זוֹ כְּמִי שֶׁזָּב מִמֶּנָּה דָּמִים הַרְבֵּה:
A woman becomes impure due to factors beyond her control, whether for niddah or for zivah. What is implied? For example, she jumped from place to place; she saw animals, beasts, or fowl copulating, was aroused, and began bleeding. In these and in other analogous instances, regardless of the situation, since she experienced bleeding, she becomes impure. She becomes impure from even the smallest amount of bleeding. Even a drop of blood the size of a mustard seed [makes her impure as if] much blood had drained from her.
