Red - Red is about passionate love, sex.  You use red when you are in a passionate relationship or if you want to spice up your relationship sexually.  Red in Health magick is geared toward your organs - heart, liver, kidneys. So, when you are doing magick and spellwork for those areas and ailments, a red candle would do in a situation like this.  You can also use Red as energy, if you are good with visualization.  If you want to be with someone (your partner, preferably--magick used on the unknowing is just not cool) you can visualize red energy from yourself to your partner. Close your eyes, see the red beam of light coming from your solar plexus to their solar plexus, not their root chakra - that is too intense for most folks.  The solar plexis is right where the ribs end, drop dead center of your body.

Orange - Orange is a friendly color and the color of success and communication and movement.  I use orange when I want a new job, home or success in an endeavor.  It is also useful in court cases.  If you wish to open communication channels, orange is your color.  Orange in health spells is geared toward children.  Healing children in bad situations, social problems.  I know a social problem is not a health issue, but it can become one later on.  It's a brain thing...social activity that had been crippled can be remedied by using orange in a health spell.  But again, orange is good for new successes....
not just health, but new employment and such.  Orange is all about success.

Yellow - Yellow is THE brain color.  Yellow is about happiness, joy, music, arts, breathing freely.  If you are an artist having some kind of block Yellow is your color.  If you suffer depression, yellow is your color.  I would use yellow in several spell instances. General happiness, easing malaise, bring joy back into my life.  And in health, it is the KEY color for ailments having to do with depression, asthma, Alzheimers and the like. 
 

Green - Green is a color of prosperity, so always use green for those spells.  However, what most don't know about green is this:  in health, green is the color you use for terminal illness AND female problems. If you are doing a spell to alleviate a cancer patients pain, green is the way to go.  If you are doing a spell to help someone with their fertility problems, green is the way to go (in conjunction w/brown, but I will get into that later).  Green is a supremely powerful color.

Blue -  Blue is the color of home and peace. If you are doing a house blessing or even an office blessing, blue is your color.  Peace and protection spells do well with blue.   I don't work with blue much otherwise. Blue in health, I use for ailing the grieving.  Try to bring Peace with blue in the healing process, as in for someone after an operation or something.

Indigo - Indigo is used best for someone who is an "expert" in the field of psychic abilities.  Otherwise, I would not tamper with this color. This is a great color to open up other channels that one is ready for, like speaking to the dead, seeing futures, reading.  In health, it is probably the best color for someone who is schizoid or has other mental problems.  I would NEVER use this color for anyone unless it was a healing spell...and this is from someone who is pretty psychic and knows what it is about.

Violet - Violet is a good color for the starters.  For someone who has some knowledge of tarot cards or whatever they are into (astrology, etc)...this is a good color to help enhance  psychic abilities, open channels but not to the point of excess. It is a lovely enhancement if you use it that way.  Violet is also great for GRAND wealth.  Violet does NOTHING on a small scale, so DO be careful when using it.  I would stick to using it for psychic enhancement 
Violet in the health department is best used for things like fatigue, FM, MS, CFS and things like that. 

Pink - Pink is the color of Universal Love.  Not the kind you want with your sexual partner, but the kind you have for your friends, children, and pets.  Global love, even.  I would use pink when wanting to express love in an affectionate and caring way, not sexually.  In health, I would use pink on someone who has lost the inability to laugh, feel joy.  Those who lost the simple innocence of loving something.  Bitter people come to mind.  You can also send pink energy to friends and such as explained earlier.  This makes people feel warm, loved, accepted.  This is a great tool in helping others. 

Brown - Brown is tough. I don't recommend ANYONE using brown in magick unless you really know what you are doing.  Brown should only be used in healing magick in conjunction with green for female healing, as in  someone trying to conceive.  Brown is also used in severe cases of justice and karma...unless you know what you are doing, you best not tangle with that in magick!  I only use brown when involved in a court case or something.  It can be extreme.  In my way of doing magick, it is best used in the negative force...which I am not going to get into here.  It's stronger when used in the negative hand.  So, brown is to be careful with.

Black - Black is another one I never allow my pupils to use...unless they talk to me first.  It is best used ONLY as a protection and not as an offensive (read=attacking) color.  Black is best used in health when someone already passed to help them leave this plane and move on to where they belong.  And it is, on some level, a form of protection when used that way.  I only use black when someone is going out of their mind and will hurt me or my family.  I rarely use it. 

White -  White is always used as a substitution... I personally don't like that.  I only use white for protections... and purity (like in conjunction with a house blessing).  It's cleansing.  White is good if you are going to do Moon magick, but even then, I might go with silver.  White in health I use for healing people who are toxic, like drug addicts and alcoholics. 

Silver/Grey - Grey is another color that I don't allow my pupils to use readily.  It is a color of neutralism and while that may seem safe, it often isn't.  Neutral indicates indifference.  It's a rare human that identifies with that.  So, I find it best to leave that lie.  I would not use this in health spells unless it was a person who wanted to die.  Rather than do the assisted death thing, I would use grey magick to help get them on their way - remember, indifferent.  Silver, to be honest, is only good as an enhancer, as in glitter to another spell.
I use silver in conjunction with house, protections and a few other spells; same with gold.  

Click here for a color associations chart.