Microgram

In the metric system, a microgram (µg or mcg) is a unit of mass equal to one millionth (1/1,000,000) of a gram (1 × 10−6), or 1/1000 of a milligram. It is one of the smallest units of mass (or weight) commonly used. The symbol "µg" (mu-g) conforms to the International System of Units and is often used in scientific literature, but the United States-based JCAHO recommends that hospitals do not use this symbol in handwritten orders due to the risk that the symbol µ might be misread as the prefix m, resulting in a thousandfold overdose. The abbreviation mcg is recommended instead.

To type the 'micro' symbol, which is a Greek symbol called mu, in most Windows-based programs hold down the Alt key while typing 2-3-0 on the keypad. On a Mac, hold down the Option key while pressing 'm.' You can also press AltGr + m on most keyboards. Using the font face named "symbol", mu is denoted by a lowercase "m": m.