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.
The white which is the brightest of whites is one which has a slight blue hue. One of the more dramatic experiments to prove this point is to place a brand new white shirt or blouse next to one which has been laundered for perhaps a year or so and notice the difference.