The evil eye is a supposed power of bewitching or harming by spiteful looks, attributed to certain persons as a natural endowment. This belief was widespread among ancient civilizations including the Chaldeans, Egyptians, and biblical Jews.
The text documents numerous rabbinical accounts of individuals possessing this power. Simeon ben Yohai and R. Johanan allegedly could transform people "into a heap of bones" through their glances. R. Eliezer ben Hyrcanus reportedly burned spots wherever he looked, including partially burning grain that fell under his gaze.
The Talmud attributes significant consequences to the evil eye's power. According to Rab, "out of 100 people 99 die through the evil eye." Large congregations were considered particularly vulnerable, which is why Joshua advised Joseph's descendants to avoid entering cities through the same gate.
The evil eye could affect not only people but also lifeless objects, such as crops and garments, and was believed to cause them harm. Blessing comes only upon those things which are hidden from the eye.
Descendants of Joseph supposedly possessed immunity. Others could protect themselves through specific gestures—"stick his right thumb in his left hand, and his left thumb in his right"—while reciting particular formulas.
Physical remedies included painting trees red, hanging foxes' tails between horses' eyes, and various ritual practices involving fire and water.
The harm that comes from the eye is neutralized by hanging something between the eyes. A piece of bread and salt or matzah from Passover was put into the pockets of particularly beautiful children, and a piece from the garment of the suspected person was placed on glowing coals with the smoke blown into the child's face.
Adults wore rings or beads of amber on a string around the neck as protection against the evil eye. The bridegroom, whose conjugal happiness is envied, is especially susceptible to the evil eye and may protect himself by walking backward.
Eastern European Jewish communities developed elaborate protective customs. These included placing bread, salt, or matzah in children's pockets, wearing amber beads, and walking backward at weddings to prevent harm from envious observers.