As doctors warn it can cause a dangerous reaction with a host of common drugs... 1  Researchers warn that grapefruit reacts with many medicines. 2  The fruit can cause devastating side-effects from stomach bleeding to kidney problems. 3  Doctors say the public is ignorant to the dangers and putting themselves needlessly at risk.
According to the definition of the question (based on light reflection and not light emission), a well-polished mirror is the the whitest substance on earth. The main reflection layer is usually made out of silver.
Light with a spectral composition that stimulates all three types of the color-sensitive cone cells of the human eye in nearly equal amounts appears white. White is one of the most common colors in nature, the color of sunlight, and the color of sunlight reflected by snow, milk, chalk, limestone and other common minerals. In many cultures white represents or signifies purity, innocence, and light, and is the symbolic opposite of black, or darkness.