Consist. Comprise. Constitute. Compose. All four words are verbs, with slightly different meanings. When defining each word, many dictionaries use one of the other words in its definition, making it even more confusing. When choosing when to use which, consider the following.
Consist
To consist of something is to be made up of it: A lethal dose of nerve agent VX consists of only 10 milligrams.
Comprise
To comprise something has the same meaning as to consist, often implying that the whole is regarded from the point of view of its individual parts: The chain is comprised of many links, and is only as strong as its weakest.
Constitute
To constitute something is to form a whole, especially of dissimilar components: Love and hate can constitute a balanced relationship.
Compose
To compose means the same as to constitute, but implies that the components have something in common: Water is composed of hydrogen and oxygen.
Hate on comprise.
An interesting history of sense development concerning the word comprise has caused confusion, if not hate for the word itself. The most common mistake is confusing consist and comprise with each other. To say A lethal dose of nerve agent VX comprises of only 10 milligrams, is wrong because it is not analyzed from each separate component or milligram, but rather as a whole dose. In fact, there is a lot of skepticism and criticism of the word “comprise” all together. “None of the many neat schemes purporting to describe its correct use seems accurately to describe the way Standard English users actually employ comprise.” (Bartleby) Thus it is suggested to use constitute and/or compose as active verbs, while consists and/or includes as passive. However, if your use of the word can clearly indicate its context, separate from the its other accepted use, choosing a substitute is not necessary.
Also, ”Comprises” is better grammar than ”is comprised of.” “The whole comprises multiple parts” is better than, “The whole is comprised of multiple parts.” Even better though is, "Multiple parts comprise the whole."
However… Usage determines meaning.
Sources:
http://www.tiscali.co.uk/reference/dictionaries/english/data/d0081813.html
http://www.bartleby.com/68/3/1403.html
This form as a guide, not as a source: http://forum.wordreference.com/showthread.php?s=2248451b8ad7f34f6a3e881962f5af91&t=47429