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.
VantablackÂ® is a super-black coating that holds the world record as the darkest man-made substance. It was originally developed for satellite-borne blackbody calibration systems, but its unique physical and optical properties have resulted in it finding widespread application.