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.
adjective, whiter, whitest. 1. of the color of pure snow, of the margins of this page, etc.; reflecting nearly all the rays of sunlight or a similar light. 2. light or comparatively light in color. 3. (of human beings) belonging to a group marked by slight pigmentation of the skin, often of European descent.